The film opens introducing us to Frank Sullivan, a firefighter who takes risks which his colleagues might call ill-advised if not unnecessary.  He cares about people, and we can see that one of these days he's not going to come out alive.

It's October of 1969, and as October 10th arrives, solar flare activity is at an all-time high such that residents of New York City can actually see the Aurora Borealis.  This combination of solar flare activity and the presence of the aurora is the pseudo-scientific explanation for the events which follow.  Tonight, October 10, 1969, Frank Sullivan is going to talk to his son John; but he's going to use a ham radio to talk with him, and John is going to answer using the same radio on the same day thirty years later.  The film never really explains why John Sullivan and Frank Sullivan are able to communicate with each other, but it implies that it has something to do with that aurora and the freakish reception consequent.  I'm not a ham radio operator, but it seems to me that solar flares make reception more difficult; but it's at this point entirely fantasy, so we take the premise:  Somehow they are able to talk with each other.

And this is why there is a temporal anomalies problem.  It is very important for the reader to understand that communication with the future is functionally the same as travel to the past.  As most people miss this, we'll take a moment to consider it.

I have many times said that travel to the future has no affect on time at all.  If I leave 2000 and travel to 2020, it will be the same as if I moved away or took a nap for twenty years, but that I haven't aged.  I won't be able to find out what I did in that time, because in fact I did nothing in that time--I vanished in 2000 and reappeared in 2020.  I've had people argue this with me; they remind me that by going to the future I learn things about the future I would not otherwise know.  I immediately point out to them that that is not the part that matters.  Everyday I learn things I would not otherwise know.  Today, in fact, I learned that we had two boxes of confectioners sugar that needed to be put away.  There's no problem with that unless and until I take that information back to the past.  Taking information to the past creates the danger that the future will be altered; and if the future is altered in a way that materially changes the information, it runs the risk of undoing key events.  If I came forward to today and discovered the two boxes of confectioners sugar still packed, and then returned to a few days ago when my son was making a cake, I might well have told him where to find the sugar, and he might have used it, and consequently it would not be here for me to discover today, resulting in me not having that information in the past to give to him.  Thus the movement of that information from the future to the past creates an infinity loop, an anomaly in which time repeats in perpetually alternating histories.

It should be apparent at this point that it is not necessary for a person to travel from the future to the past to create an anomaly; it is sufficient for information to do so.  In most of the films we've seen, the problem occurs because someone travels to the past (or from the future to the present); but in this one, no one ever makes the trip, creating havoc merely by transmitting information to the past.

But back to the story.

In 1999, John has had a strange day.  His girlfriend Samantha has just dumped him.  He comes home to find his childhood friend Gordo, along with Gordo's son, waiting in the house--the same house in which he grew up and now lives alone.  Gordo bemoans his failure to invest in Yahoo when it was cheap, and they ask to borrow John's tackle for a fishing trip.  They stumble on the old radio in a trunk in the closet, and set it up, but can't fix it before Gordo's wife pops in to chase her son home to bed.

And while John is alone, the radio starts working, and he has a chat with a guy named Frank, a baseball fan from Queens who doesn't know how the Mets won the '69 World Series.  So John recounts a few critical details of that first game.

I'm not a baseball fan; and I'm aware of the idolatry which is sports fandom in the United States.  But I find it a bit difficult to believe that young John cared one bit for the World Series in 1969, given that his father died in a fire during the middle of the second game.  But the film wants us to believe that he was enough of a fan to know the events of at least the first two games vividly, and it's not impossible.  But then, I find it difficult to imagine that a guy who lost interest in the game probably a decade before would recount the events of an old game with a stranger over a radio even if that game hadn't been held during the most painful days of his childhood; and perhaps it could be argued that he remembered because of those events:  "My dad died, but at least the Mets won the series."  If that sounds hollow to you, I agree; but grief is strange, and people have had stranger reactions.

Meanwhile, John's job as a police detective takes him and his partner Satch, an old family friend, to the grave of a missing person uncovered at a construction site.  He has a talk with some of the neighbors, an elderly couple who have lived there for over thirty years.  It seems almost unimportant at that point in the film, as if they're trying to fill time with day-in-the-life-of-a-cop stuff.  It's not.

The next day in 1969, Frank watches a baseball game unfold exactly as his new friend John had predicted.  That night he has to ask how it was done, how John was able to predict in detail what was going to happen at the game.  John thinks he's crazy; the game was played thirty years ago, and Frank is talking like it's today.  He tells him how the next game turns out.  Then, while they are talking, young John comes into Frank's room to say goodnight.  Frank calls him by his pet name, "Chief", and promises to come up to sing the baseball song to him in a few minutes, like he does every night.

And at that moment, it all clicks for John.  This is his dad; and he's talking to him on October 11, 1969, the day before he got killed in that fire.  He starts asking him pointed identifying questions:  what are the call letters on your radio?  what is your name?  your son's name?  Then he spills his guts, as fast as he can--his name, his address, how his dad use to sing to him and call him chief.  And he tells his dad about the Buxton fire, a warehouse in which he was killed, and he would have made it had he gone the other way instead of following his instincts.

Frank is not impressed--not yet.  He thinks it's a cruel joke, that John is a stalker threatening his family.  (In fairness, John's first reaction was that Gordo was playing some kind of trick on him; but it didn't add up right, so he followed Aristotle's advice, preferring the probable impossible over the possible improbable.)  The desk is burned by a cigarette dropped into some spilled glue, and the burn appears in the future.  The contact is fading, but John is pleading with his dad to stay alive tomorrow.

If you've ever worked with two-way radios, you probably had your disbelief suspenders snapped somewhere along this point.  Amateur radios are built to send or receive, but not both at once.  When you "key the mike", the receiver is disabled so that it won't be overloaded from the output of the transmitter.  But this radio suddenly doesn't care whether the mike is keyed, sending and receiving constantly without reference to whether anyone is using the mike; pushing the button becomes a formality, a habit of no consequence.  When Frank tries to argue with John, he can't interrupt him, because even while he's transmitting he's still receiving the distant signal.  It's probably more dramatic, but I'm sure I'm not the only dabbler in radio who was bothered by it, and I never got past the Dick Tracy Two-Way Wrist Radio.

But it pays off for Frank.  He's at the fire station the next day watching the game unfold as the stranger claiming to be his son had predicted when the alarm goes off; and he sees that he's at a warehouse of the Buxton Seed Company.  He doesn't let it stop him, but rushes into the building in his usual reckless manner to save some homeless kid on the top floor.  He's cut off from his support by the time he throws the kid over his shoulder, and is looking for a way out.  One way is all flame, the other all smoke and darkness.  He starts into the smoke, but hesitates, the words of his conversation coming back to him.  He peers through the darkness to see a glow of hot flame under a door ahead, turns around to find a grain chute, and takes his unconscious fire victim on a ride into the river below where they are rescued by the crew of a responding fire boat.  He was dead, but is now alive.

John is at a bar during lunch, having a drink with Gordo and Satch in memory of his father's passing; they know it's a tough day for him even now, and he seems to be taking it hard this year.  In the middle of a toast to Frank, he suddenly has a flood of new memories which is very shocking, and he drops his glass.  He confirms with his friends that his father did not die in a fire; the man died of cancer in 1989, from the cigarettes he smoked all his life.

I want to say at this point that dramatically the film is well done; it's a heart-wrenching story at this point.  If it were not a temporal disaster, I could really have enjoyed it, and did enjoy parts of it.  It was worth seeing.

Frank is convinced, and that night has a long talk with John.  We're introduced to an interesting but foolish notion, that of dual memories:  John remembers everything that happened in the timeline in which his father died in the fire; but he also remembers everything that happened in the timeline in which Dad died of cancer.  No one else remembers the Buxton fire accident.  They have a long chat, during which John tells him the rest of what's going to happen in the World Series, Frank lapping up every bit of it.  John also asks his father to quit smoking, telling him that if he doesn't cancer will kill him in 1989.  Over the next couple days we see Frank make an effort to quit.

John leaves a message on his mother's answering machine to call him, and goes to bed; Frank runs down to the hospital where his wife Julia works as a nurse, to tell her he loves her and is never going to leave.

The hospital scene is extremely well done.  It seems very ordinary, but is critical to the events that follow--exactly the sort of thing to which those living through it would give little thought at the time but which would have drastic effects on the future.  Even the viewer is not aware that the patient in the bed matters.  While they're talking, she chides him for bothering her at work, despite being very pleased.  Then she's interrupted--she has to rush off to save a patient's life from the error of a doctor who is hanging a medication incompatible with something already administered.  She saved the man's life, but the focus is more on the doctor's failure to check the chart before prescribing something.

And somewhere in the future, John has a dream, a horrible dream built on unknown memories.  He awakens and calls his mother, but instead of her answering machine he gets some deli.  He is confused and perturbed.

It's at about this point that the movie becomes inconsistent in its treatment of that thirty year interval.  Some events which occur during that time are immediately part of the history from the moment the trigger event (in this case, saving Frank's life) occurs.  Others don't become part of the history until exactly thirty years after they occur in the past.  Still others become part of the history sooner than that, but based on other trigger events.  This is a case in point.  We will eventually piece together that the man whose life John's mother saved that night was the serial killer they never caught, and that in ten days he will kill her.  All of those events were triggered by the fact that Frank survived the fire.  The history originally included someone picking up Frank's wife from work to tell her that her husband died, so she was not there to save the man's life.  Thus we have a causal chain:  Frank lives ==> wife goes to work ==> patient survives ==> patient kills wife.  But for some inexplicable reason, despite the fact that Frank's death by cancer in 1989 is known in 1999 from the moment Frank makes the choice to survive the fire, the death of his wife is not part of that history (and note that her answering machine still existed before John went to bed) until exactly thirty years after not the moment she died but the moment she saved the life of the killer.  Other events which occur in the past become true in the future thirty years after the moment they happen in the past.  For example, when Frank gets home and is unable immediately to reach John on the radio, he burns a message into the table; John sees the message appear, letter by letter, in the future.  It's an inconsistency in their treatment that makes it very difficult to grasp how they think time works.

The next day, not having fully absorbed the new memories triggered by his mother's death, he goes to work.  Satch is distinctly unfriendly, but is still his partner.  That body they found the other day turns out to have been one of the Nightingale murders.  That, Satch says, makes ten.  No it doesn't, John insists; there were only three, and this is the fourth.  Satch hands him the case files, ten murders.

And on October 22, it's his mother.

John is frantic; but he has changed history before, so if he can enlist the aid of his father, he can do it again.  His mother's life is at stake.

By the end of the day, they have identified this newly discovered victim, and determined that she is earlier than any of the others, and developed a suspect list based on the supposition that she was the first.  John takes copies of the files, and lets his father know that somehow they changed history such that Mom dies.  He then passes to his father full information about the next victim--who she is, her last known movements.  If he can follow her, John suggests, he will see the killer.

Meanwhile, he attempts to make amends with his girlfriend; but she has no idea who he is, finally recognizing him as that friend of Gordo who is a cop.

It doesn't entirely work.  Frank is no detective, and he's never done anything like this before.  He makes contact with the girl and talks to her all night--saving her life, but chasing away the killer.

Undaunted, they try again the next night.

John also talks to his younger self, and to Gordo.  He tells Gordo always to remember one special word:  Yahoo.

John gives Frank complete information about the identity and last known movements of the victim, and Frank this time is more circumspect, identifying her at the nightclub where she moonlights as a waitress, and casually following her out when she prepares to leave.  But the killer noticed him the night before, and notices him again tonight, and attacks him, rendering him unconscious and removing his drivers license from his wallet.  Interrupted by other patrons of the bar, he leaves Frank alive, passing him off as drunk, and leaves the scene.

Frank revives, grabs his wallet, and rushes to the apartment of the victim.  Banging on the door, he awakens a neighbor; forcing it open, he finds the body and an open window, and flees the scene.  He returns home and tells John the whole story.

But there's good news from bad here:  the killer handled Frank's wallet.  Very gingerly Frank bags it and hides it under a loose board known only to him; immediately John is able to retrieve it from there and take it to forensics to dust for fingerprints.  He finds his killer, Jack Shepard, a cop in 1969 arrested for sexual assault subsequent to the last murder and in 1999 working as a private investigator.  He also goes to talk to Shepard's father, and discovers that his mother, a nurse, was murdered shortly before the first of the Nightingale killings.

He gives this information to Frank the next day, including the name of the killer.  He tells him to go to a pay phone and make an anonymous call; since there is reason to think the killer keeps souvenirs from the victims (bits of jewelry), a search of Shepard's apartment should uncover these and close the case.

But it's too late.  Satch has arrived; he needs to talk to Frank outside, down at the station.  Frank was seen at the site of the latest murder, and his fingerprints were found at the scene, and his driver's license was under the body.  He has some explaining to do.  He tries to tell John what's happening, but in the tussle the radio crashes to the floor and breaks--in 1969 and in 1999.  Contact is lost.

Frank doesn't try to invent anything; he tells Satch the incredible truth--and Satch does not find it credible.  If Frank doesn't tell him what really happened, he's going to be convicted of a series of murders.  And this nonsense about talking to John from the future is exactly that:  nonsense.

Frank offers to prove it.  The proof he offers is his knowledge of the events of the ballgame right now on television:  a player will be hit in the foot, another will hit a double, and there will be a home run, and between the seventh and ninth innings the Mets will come from behind to win.  Satch is unimpressed; but at the moment, Frank's wife has arrived to find out what's happening, and Satch leaves to chat with her at a coffeeshop.  He asks about the victim, about the radio, about John.  Frank's wife doesn't know anything about it; the John on the radio is just some friend of Frank who happens to have the same name.  But while they are talking, the game is on the television, and Satch becomes aware that a player has just been hit in the foot by a wild pitch--the events described by Frank are happening.  Satch turns his attention to the game.  His friend's story is beginning to gain credibility.

But while Satch (and every other cop in the precinct) is watching the game, Jack Shepard arrives to attempt to kill Frank, but he delays because he wants to know how Frank found him--and that delay derails his plan, because someone from the precinct steps in, interrupting him, and wanting to know what a cop from another precinct is doing in his interrogation room.  Shepard makes up some story, but it gets him out of the room long enough for Frank to plan an escape--the details of which are not important at the moment, beyond that he is able to leave the building after stunning Shepard.

Frank beats Shepard to Shepard's apartment, and so is hidden there when Shepard enters.  Shepard checks his stash of souvenirs, which tips Frank to their hiding place; but in recovering them, he is heard, and so begins a chase.  Frank drops the box before leaping from the window to the fire escape, and Shepard empties his gun in a vain attempt to shoot between the metal steps and at a moving target.  (I count eleven shots, which doesn't match any gun with which I'm familiar, but the action is a bit confused and I might be counting one or more shots twice.) Satch and his partner have by now figured out where Frank is, and hearing gunfire come through the door in time to find the dropped and broken box of souvenirs.  They pursue the fleeing suspect.

The chase ends in a fight in the river, and Shepard vanishes under the water.  The police are dredging for the body as Frank returns home and makes repairs to his radio.  Magically the radio in the future reshapes itself and again works.  He calls John, to give him the good news.

Not so fast; this change of events has not yet reached John, and he suspects it's not over.  While he's trying to figure it out, Jack Shepard arrives at the house--both in 1969 and in 1999--and attacks Frank and John.

His battle with Frank is brief; hitting him from behind, Shepard soon has him handcuffed to a solid object, and turns his attention to attacking the wife.  His fight with John isn't going as well.  And our radio oddity plays a part in all this, as each can hear what's happening on the other end.  Jack Shepard hasn't figured it out; he just knows that Frank knows who he is in 1969, and John knows who he is in 1999.

Frank escapes his cuffs, and grabs a gun; but Shepard uses little John as a shield.  Frank puts down the shotgun, but John's mother leaps on the killer holding her son, and John runs free.  Shepard charges Frank as he retrieves the weapon, and as Shepard grabs the barrel the gun discharges, destroying his right hand.  He then flees the building.

It is with his right hand that he is throttling the older John in 1999; the hand begins to wither, and he stares at it aghast.  John gets free, but before he can recover Shepard has scooped up one of the two free pistols, and is about to shoot John when a gun is fired.  Frank, now thirty years older and saved from his 1989 cancer death by his decision to quit smoking, has entered the room with a rifle, and saved his grown son from the killer.

There is a closing montage which looks like they all live happily ever after; but the details of that are very unclear.  It does seem that John has been married to Sam for some time, and that they have their own son; that both of his parents are alive to enjoy their grandchild; and that Gordo is a bit wealthier thanks to his Yahoo! purchase.

And that brings us to trying to understand it within the context of our theory of time travel.

Two-way communication between future and past actually creates more complications than simple time travel.  This is counter-intuitive, and so bears explanation.

If I travel from the future to the past, I have suddenly appeared in the past, and any actions I take flow from that trip.  I can interact with those now in my present, and react to their responses.  But if I send a message from the future to the past, it arrives and so alters history.  People respond to that message.  When I send my next message, it is into the world already altered by the previous message.

What this means is this.  Frank initially picks up the radio and calls for anyone who can hear him.  John, thirty years later, answers.  That message, no more than an "I hear you", changes history by being heard in 1969; and Frank reacts to that by replying, establishing a new timeline.  But now it cannot become 1999 again until all of history has been rewritten to account for that change, Frank's response to John's message.  John cannot reply to Frank's answer until that new timeline is established, and therefore Frank cannot hear that response in this timeline.  Once those thirty years elapse, John will send another message to the past which Frank will hear, and as Frank reacts to that message another thirty year history is created, waiting for John to grow up in this again altered world and be able to hear that response and send yet another message.

In several instances in this film, this factor is minor.  Critical information is usually conveyed in a single statement; it's thus reasonable to treat the communication as one message.  The key events of history are changed in the timeline following that one point in the message, and otherwise time is not much altered.  For example, in the second message, all the information about the second ballgame just means Frank learns he's talking to someone from the future.  It is that final message, in which John tells him that he died by following his instincts, that changes the critical moment in time.  Thus we will treat the majority of these conversations as single-event messages.

It might be argued that each vibration sent from the future to the past is a separate change in history; and it might be so.  My inclination, however, is to assume that each block of the message is sent back as a unit--that is, John speaks a sentence or paragraph or other uninterrupted unit of information into the microphone, and that message travels back in time; it appears as a series of waves of electrical energy converted to sonic energy over a few seconds of time because that is what it is, and it cannot appear as anything else.  To compare it, if we suppose that a time machine works like a teleporter, dematerializing the subject systematically and then re-materializing the subject at the target, it is logical that some portion of the subject must materialize first, however rapidly the materialization occurs; but that time does not have to advance to the transmission point before the rest of the subject can be dematerialized and transmitted.  Just as the dematerialization of the subject in time travel is a single event, so the statement of the message unit is a single event, transmitted as a block to the past, and received as one unit.

Thus the first contact between John and Frank, although it sets up a set of altered timelines, may be rectified into one major change in time; and the only difference between this new CD timeline and the original AB timeline is that Frank will know the outcome of the Mets game before it happens, and will attempt to contact John again the next night to find out how he knew.  Since that timeline has to play itself to the end before John can answer, the contact will go unanswered in this timeline, CD1.

But once CD1 plays itself out, John does hear that call and replies again.  There is an exchange of messages about baseball, each one setting up a new timeline insignificant in any meaningful way, and then young John's interaction with his father becomes part of the history.  John starts asking questions, and soon (although multiple histories later) knows that this is his father.  His attempts to demonstrate it, whether or not convincing, aren't important, because his father will die in that fire tomorrow; but then he tells him of the Buxton warehouse fire, and changes history.

It helps the application of our theory that Frank is unable to interrupt the important part of John's message; John tells him the details of his death in the Buxton warehouse fire and how to avoid it pretty much all in one breath, so there is one critical change in the timeline, and Frank, convinced by Al Weiss' RBI, makes the choice that saves his life.

The situation becomes very complicated at this point.  John has created an infinity loop.  We had a timeline in which Frank died in the fire, the radio was put away, and John grew up with his mother.  Then on October 12 we saved Frank, creating the timeline we should label CD2.  In this timeline, Frank lives and teaches John to ride his bicycle and much more; his mother also lives.  Frank dies of cancer in 1989.  And then when we get to October 10, 1999, John stumbles into a talk with Frank, and the CD1 line replays but resolves itself.  (A timeline resolves itself when future causes of past effects are supported by the timeline created by those past events.)  And then on October 11, Frank calls back to ask John how he knew, and John figures out that Frank is his father who died of cancer in 1989; and the most pressing thing John can think to tell his father is that he needs to quit smoking.  John doesn't know that his father died in a fire; that history has been erased, and never happened.  So the next day Frank dies in the fire, and that becomes critical in John's life, so that he will warn Frank when he gets the chance--and we are trapped in repeating timelines.

The movie proposes a solution to this:  dual memories.  According to John, he can remember everything that happened in the old timeline in which his father died; but he can also remember everything that happened when his father survived the fire.  This is not possible under my theory; but for what it's worth, it's not possible under any other popular theory, either.

Under my theory, John can't remember the events of the alternate timeline because although they really happened, they've been erased as they were replaced by the new history.  Just like everyone else, John remembers only the history that flows from the events of 1969 which he caused when he sent information back.  Thus he cannot remember his father dying in a fire in which he didn't die.

Under the fixed timeline theory, the entire situation is impossible.  A fixed timeline theory proponent would have to say that Frank would have gotten out alive, but John's warning that he shouldn't follow his instincts but should go the other way sent him into the fire.  That would be a very short movie and a very bad story; it also doesn't fit with our understanding of causality:  if John were to give his father sufficient information to survive the fire, why could he not save him?

The alternate dimension theory faces perhaps the most difficult challenge here.  It must be assumed that John is sending information not to his past but to the past of another timeline.  But if that's the case, the result should be that he saves Frank in that other dimension, but his own father still died in the fire.  We can imagine the confusion this causes, as Frank is saying he's still alive, but John is saying he still died.  The only alternative to this is that somehow when John sends the information to Frank, he becomes the John of the other dimension, somehow traveling laterally across dimensions himself.  This makes no sense whatsoever--there is no reason to think that John has moved at all; even if he did, he would not have dual memories, but would have either false memories from another dimension, true memories of the new dimension, or true memories of his own dimension which did not match the history of that other world.  So again, with the alternate dimension theory this entire situation is impossible.

So time is destroyed, and ends here.  But the movie continues.  (Although Sliders once did an episode in which they actually destroyed the fabric of time in one world, that's not usually a satisfactory ending for a story.)  So we will continue our analysis.

There seems to be another mistake here.  The next conversation occurs that evening; but time must move forward from 1969 to 1999 before John can send that message.  And it appears that John's mother dies because his father lives.  Thus it would seem that John's mother should have died at this point.

But perhaps it's not quite so erroneous as it first appears.  It is not the fact that Frank survived that results in his wife's death; nor is it the fact that she went to work.  It is because she saved the life of the killer that she was killed.  It happens that she saw the medication being hung at the moment she was talking to her husband.  We could suggest that the survival of Frank meant she went to work, but that the patient would have died had she not been delayed by his visit; and since he didn't visit her until after he spoke with John, it's reasonable to suggest that the conversation with John altered history in that regard:  either he did not visit his wife at work, or he visited her at a different time (probably earlier).  Either way, since he wasn't there when the medicine was hung, she didn't catch it.

There's still a mistake; even on this rendering, once John and Frank have had their long talk, mom is dead; John will not get her answering machine before he goes to bed, because that thirty year history has now happened.  It isn't that everything is going to happen, but that it has already happened for John, however it will happen without his interference.

And that means that John is wrong.  It isn't necessarily that Mom died because of something Frank already did; all we know is that Frank's survival results in Mom's death.  John can't know that it isn't something Frank is going to do, or even that the girl who would have died in the fire won't do something that changes these events.  Everything Frank does now is new, creating ripples of change throughout the world; but for John it has all already happened.  The killer could be saved in a fire rescue; or someone who stopped the killer might not have been saved because Frank led the rescue team instead of someone else.  The possibilities are too complex for so simple a reaction as John gives.  But it happens that John is right.  Every movie is entitled to one incredible coincidence; this one may have just used it.

So time advances once again, and this time John grows up with his father alive but his mother brutally murdered; and his father probably wondering why when John told him from the future that he (Frank) was going to die in the fire, he didn't tell him that his mother was going to be murdered.

The fact that Frank is now alive raises another question.  After Frank's death, Satch took a strong interest in assuring that John grew up well; and John became a police officer like Satch.  It's not at all clear that John would have become a police officer had his father lived; on the other hand, the death of his mother might have played a role in that as well, so it's not certain either way.

John's mother is now dead.  The speed dial on his telephone is set for a deli instead of his mom's house.  His girlfriend doesn't know who he is at all, beyond that he's a friend of Gordo and Linda.  Satch is still his partner, but their relationship is a lot more strained--there's an implication that John now drinks too much, although he doesn't seem to be aware of that.  It is now that John discovers his mother was murdered; it's another coincidence, because that body they happened to have found a couple days ago was identified with the same serial murder case.  However, this seems much less striking a coincidence.

The next conversation, broken into individual messages, creates havoc.  We'll take it bit by bit.  The first message is, "Dad? you there?  Can you hear me?  Dad I need you to be there."  And that's the end; Frank never hears another word from John, and the events continue as before--except perhaps that Frank thinks John tried to tell him, but the radio failed.   The next several messages increase this, but don't provide any information:

"Listen.  There's something I need to tell you."

"Something happened, something pretty bad."

"Mom.  Something happened to her."

"She's not here."

"She died; but it's like it just happened, though."

"No, Dad, it happened a long time ago, long time ago for me."

"Oct 22nd.  1969."

This last statement could well change history.  If that's all Frank knows, he will probably stick to his wife like glue on that day.  He might never know how she would have died, but he will keep her alive.

And in keeping her alive, he creates another infinity loop.  John's mother didn't die; the serial killer had nine known victims, not ten, and there's a lot less urgency for Frank to do anything.  No longer having the information that his wife died, he doesn't save her, and we're caught in the loop.

And so the next few messages are never sent; that date information will probably save his mother's life.  If not, one of these messages will provide Frank with enough information to protect her:

"She was murdered."

"Listen to me.  There was this case.  A serial.  They never caught him.  But he murdered three women, all nurses, between 68 and 69.  They call him the Nightingale."

"Dad, dad, we did something, something to make it worse."

"Listen.  He didn't just kill three women anymore.  He's killed ten.  Something we did changed the past."

"What--just think about it.  Everything you did is different than what would have happened if you would have never gotten out of that warehouse.  Now what'd you do last night Dad?"

"Oh, $#!+.  That's it.  She wasn't supposed to be there.  Butch went and got her 'cause that was the night of the fire, and he brought her home."

"I'm saying that's just the beginning, it could have been anywhere, anyplace, time that she wouldn't have been if you would have died."

"What about the others?  What about the others, Dad?"

Frank suggests warning the others, and doesn't hear another word from John.  But he can't warn them anyway, because he doesn't know who they are, so this won't change history.  It's likely that Frank will take his wife away for the day.  Of course, this assumes that we overlook the infinity loop already created.  Either Frank has failed to save his wife, or he has erased the information on which John bases his messages.  But we'll continue:

"That'll never work; they'll just think you're crazy."

"No, because...."

"Nobody got any--hold on, wait a minute.  Dad I may not know who he is, but I know where he's going to be and what he's going to do before he gets there."

"They will if they catch him in the act, and you can make that happen, Dad."

"Well I'm a cop.  This is what I do, this is something we have to do."

"Then you get mom the #=!! out.  But dad, those other women were not supposed to die.  If we don't do something, to try to stop this guy, we're going to have to live with that the rest of our lives."

And at this point, Frank is more and more persuaded that he has to try to save these girls; but until the next timeline, he can't help.  He will take Julia and leave town for a few days.  She'll probably object that neither of them can get time off on such short notice, but it's very important to him, so he'll prevail.

The next message, the last message of this conversation, gives complete information and instructions on how to save the next victim, Kerry Reynolds.  Frank succeeds in saving her; but he doesn't succeed in finding the murderer.  Since in this timeline he won't hear from John again, he'll pull Mom and run.

The next message again makes only minor changes; it is eventually hinted that Gordo buys Yahoo! stock, as he has a Mercedes in the final montage, but he hasn't become so rich as to move out of the neighborhood.

Frank's second attempt to find the killer goes very wrong.  The killer spots him, and attacks him.  At this point, Frank is in big trouble; it is the inevitable chain of events that his license will be found under the body of the next victim; that he was seen following her out of the bar and seen at her apartment; that his fingerprints were all over the murder scene with no explanation.  Satch will arrest him and question him; and Frank does not yet know the identity of the murderer.

It is within the realm of possibility that it could be resolved in his favor.  He knows that the other victim was found behind the construction site (although we never saw John tell Frank this, we do see him tell Frank to give that information to the police).  Frank still has his wallet, and the killer's fingerprints might be lifted from this even in 1969.  And he already knows the outcome of the World Series in minute detail, so he can verify his story to Satch.  They might catch Jack Shepard, even with such slim evidence; they probably won't convict Frank, and probably won't even put him on trial.  He might even be able to save Julia.

And of course we have to get past the infinity loop already established; but if we allow that, once history has played out John will send another message back with the information about Jack Shepard.  This plays out much as we see in the film, through the escape and the chase.

There is the matter of the broken radio.  It falls to the floor in 1969 and breaks, and at the same moment ceases to function in 1999.  This is foolish.  If Frank never will fix the radio, then it will never work for John in 1999, and we have an infinity loop that encompasses the entire film.  If Frank will fix the radio (as seems certain at this point), then John's radio won't suddenly break in 1999 when Frank's hits the floor.  It makes no sense.

  This might make sense were we to treat the radio as a magic device.  In that case, communication across time is possible because it is one device that exists partly in each time period.  When Frank drops his radio, he would actually be dropping half of the device, and damage to that half would repercuss to the other half in the future.  But as magical and inexplicable as this communication is, there is no indication that we are to take this as some sort of linked pair of magical time communicators.  It is always one radio, and we are to think that because it broke in the past and has not yet been fixed in the past that it must still be broken in the future.  This overlooks the fact that every event which will happen between 1969 and 1999 has, in 1999, already happened; and therefore the radio which will be fixed later that day in 1969 was only broken briefly years before in 1999 and shouldn't stop working.

But Jack Shepard survives the chase and comes back to kill the Sullivans.  John can't warn them in this timeline, because it hasn't played through yet; and if he does warn them, he could create an infinity loop--and yet it might not be so.  After all, if young John survives the attack at his home, he will certainly remember it and be able to warn his father that it's coming.

But as it happens, it's probably insignificant.  John's warning comes too late for Frank, who is hit from behind before he knows what's happening.  In fact, for all the communication which passes between future and past during the fight (each theoretically setting up a new timeline), only two message units might change history; and they are entirely incidental.  The sound of gunshots going from the future to the past might be what revived Frank; but he might have awakened anyway.  And at a critical moment, Jack Shepard is distracted by his own voice coming from the future, saying "Time to die, Sullivan," and this gives Julia the opportunity to jump her attacker--something she would have done anyway, and successfully, although it was more dangerous in that timeline.

Shepard gets his hand shot off, and it withers away in the future, allowing John to wriggle free.  This is just wrong.  Assuming Shepard survived having his hand shot off and isn't still in prison for the Nightingale murders (there seems to be a pretty solid case against him at this point, and he's going to need medical attention for that wound, so he's going to be caught), his life will have changed drastically, including the events of the past few days in which John confronted him about the murders.  Besides, in thirty years, he's either going to learn to work without that hand or he's going to get some sort of prosthetic device to replace it.  John doesn't suddenly escape because his attacker lost his hand thirty years before; that hand has been gone for thirty years, and the attacker is certainly not surprised not to have it now.

This doesn't mean that John doesn't escape; even if it's only the sound of the shotgun and his own distant scream that shocks Shepard, John might still wriggle free.

And in the end John's father appears and fires the final fatal shot that saves his son's life.  But this only happens because of that last sequence of messages still transmitting.  Certainly because he quit smoking he's alive today (but John would have known that before now).  But he only knows that John is in trouble right now because thirty years ago he heard that message.  And that begs the question:  why didn't he just warn John a couple days ago that Shepard was going to come after him?  He knows the date, probably even the time; and John and Satch could easily arrange to have the police waiting.  But for whatever reason, Frank remembers at the last minute that his son is in trouble, and shows up to save the day.

The montage is a nice touch; it fills us with bits of memories of the world as it is when Frank and Julia survive, when John isn't scarred by the early loss of a parent.  Like Jabberwocky, it puts thoughts in our heads, although we aren't quite certain what they are.

But as smoothly as the movie flows, and as well done and enjoyable as it is, it's a string of temporal impossibilities under every theory of time travel; time would not survive this story.