The date is given as June 27, 2019, which at the time the film was produced was a couple years in the future.  Claudette Josephine Walker and Sebastian Jefferson Thomas conduct their final failed experiment in time travel, and we learn a bit about how it is done.

Each of the time travelers wears what is called a "TRP", which apparently stands for "temporal relocation pack".  These are poor kids in a poor neighborhood.  The packs are fairly standard school backpacks in which the pair have constructed their devices using borrowed and scavenged parts (Mr. Lockhart tells them that whatever they took from the school lab they must return intact).  In the same garage, Sebastian's grandparents', where they are working on these they also run a private market in electronics, including computer repairs, cell phone batteries, and other equipment and devices, which probably gives them cash for some of their acquisitions.  There is a lot of talk about how the one bottle is filled with protons stripped of their electrons--effectively plasma--which powers the device, and how in doing so the device creates a black hole, dissolves them so they can pass through it, and reconstructs them at the other end.  The packs are connected to controllers worn on the left wrist which have the appearance of having been cobbled together from cellular phones--probably intended--and which appear to be connected by what looks to be fish tank air hose, although I suspect it's supposed to look like fiber optic cable.

The travelers also wear goggles similar to those worn by drivers in the early automotive age and pilots of open-cockpit World War I-era aircraft.  Although this makes little sense if they are being disintegrated and reintegrated, whenever a trip is successful there is an explosion-like blast at both ends, so eye protection is appropriate.

Usually they depart from an alley within walking distance of the garage, because there is rarely anyone in it except occasionally a man with a Carribean accent who appears to sell various international flags from a stand next to which he is usually sleeping.  A couple times they depart from the garage, but the explosion makes a mess of the garage and after the first such departure they were sternly warned not to cause another explosion there.  They always arrive in the same place from which they departed.  Once they are in the past the wormhole will remain stable for ten minutes, so they have to accomplish whatever they want to do and return in that time, but it appears that the wormhole is attached to them, that they can return from anywhere, but that they make a point to do so somewhere where they will not be seen vanishing or appearing.

It is apparent early on that Claudette, sometimes called CJ, is impulsive and perhaps hot-tempered.  She often acts without considering the consequences.  Sebastian, sometimes called Bastian or Bash, stands as the usually ineffective voice of reason, but has been her best friend probably since grade school.  His parents are both dead, as is her father, and although he lives with his grandparents her mother regards him as a member of their family.

Two days after that failed test--June 29, 2019--Claudette and Sebastian conduct test number 104, and this time they manage to travel back one day, to June 28th, where they make fools of themselves asking everyone what day it is.

In the interim we have seen some of the events of the 28th.  Sebastian and Claudette were in a local bodega when her ex-boyfriend Jared and his new girlfriend entered.  He has been spreading the claim that he deflowered her, and she is very angry with him, claiming that she is still a virgin, so the two of them get in a fight.  Her brother Calvin intervenes before it becomes too serious, and she's angry with him for treating her like a helpless girl, but everyone leaves without incident.

Perhaps because the bodega is the place to go, the time traveling Sebastian and Claudette wind up there when Jared enters, and the impulsive Claudette fills a cup with Slushie and throws it at him and the new girlfriend.  Sebastian sees trouble coming, and drags Claudette out the back before they encounter their younger selves, but Jared follows and pursues them.  Jared is hit by a car, and the time traveling duo races to make their wormhole escape.

Returning to the next day, they learn that Jared broke an arm in the accident, but was otherwise all right.  He is not happy with Claudette, and now has his arm in a sling, but Claudette is persuaded that they have not made any "major" change to the timeline.  They have their operational time machines, and if they can do the recharging and recalibration, they can demonstrate them at the science fair in what is now less than a week away.

The science fair must have been on July 5th.

With the neighborhood still reeling from the fact that Francis Pierre was shot by a policeman apparently without real provocation and while unarmed, the police themselves are also on edge with concern about reprisals, setting up some very tense moments one of which proves fatal.

Claudette's brother Calvin Walker was downtown with his friend Dennis on the 4th of July, and the two started walking presumably home.  Outside their knowledge two black men in ski masks robbed the bodega and fled their direction; Calvin and Dennis commented on them as they ran past.  Police in pursuit saw Calvin and Dennis and ordered them to stop.

Calvin shares his sister's stubbornness.  Police demanded identification, and he glared at them.  Eventually he reached for something, and one of the two cops, on edge, shot him.  He dies.

We have family drama and mourning, a funeral for Calvin, and then the fateful words spoken to Claudette:  "I would go back and fix it If I could."  Claudette realizes maybe she can.

It has been established that the proton power pack can only take them back one day, and it has been longer than that since Calvin was shot.  However, Claudette begins drafting some daring redesigns, adding a second cannister in which she intends to reverse the spin on the protons creating antimatter, which when released to interact with the plasma will create a high-energy matter-antimatter reaction.  (In the film one of them incorrectly identifies those anti-matter particles as positrons.  Positrons are anti-matter electrons; the correct name for what they are creating is anti-protons, and they would have known this.)

She persuades Sebastian to help her with this, and he agrees to go with her.  The estimated new range for the packs is a week, and with recharging they can attempt one trip each day, so they have time for a couple tries.  The shooting is said to have been five days before as they leave.

The new idea works, and they wind up in the right place at the right time, and begin running.  Their plan is to find Calvin and get him away from the approaching police before the bodega robbery.

Unfortunately, as they come around a corner they run into ex-boyfriend broken-armed Jared, who is there with his gang, and they are quickly surrounded.  Knowing how little time they have, Claudette strikes Jared's broken arm, and the two run--but they have to evade pursuit before they can get to Calvin.

As they approach, Calvin is shot.  Sebastian has to stop Claudette from running to him, and they return to the future not having fixed anything.

Sebastian then suggests something completely original in time travel theory:  if they can run enough power through the time machines, then their trip to the past would create enough quantum energy to erase their previous trip to the past.  This would enable them to travel to the same place and time without encountering their other time traveling selves.

Obviously I'm skeptical.  It isn't just that I don't see how or why that would work; I don't see why Sebastian thinks it would work.  However, it forces a step in the plot, as in order to handle that much power they are going to need Eduardo.  It also enables the story to return to the same point in time and space without juggling the problems of Claudette and Sebastian having to avoid their previous time traveling selves.

Eduardo to this point has been a side character, a sort-of friend who has had a crush on Claudette since early grade school whom she thinks is creepy.  He also excels in science, and Mr. Lockhart gave him an A for his science project, in which he created a circuit board capable of handling a tremendous amount of energy.  (I think at this point the film is taking advantage of the ignorance of the viewer.  A circuit board is not like a USB cable or a car battery or something that would be interchangeable; each circuit board is built of components to do a specific thing.  Your computer's video controller is built on a circuit board, and its audio on a different one, and the processor chip is mounted on another, the "mother board".  Audio amplifiers and electronic keyboards and radios and audio and video players all have circuit boards, and they're all different.  However, for some reason what matters about Eduardo's circuit board is not what it does but that it can handle huge amounts of electricity--which does make it unique, circuit boards generally comprised of components that function at relatively low power.)

They tell Eduardo that they need his circuit board, and the bargain includes that Claudette will go out on a date with him.

For whatever reason, the newly enhanced TRPs take them to the same time and place without having them encounter themselves.  This time the plan has changed:  Claudette calls the police and tells them that the bodega is being robbed.

Not satisfied with that, Claudette insists that she and Sebastian go watch the arrest.  They are waiting on the sidewalk outside the bodega, but the police are still nowhere in sight.  Unhappy with this, and impulsive as ever, Claudette tells Sebastian to wait for her while she goes inside to warn bodega owner Carlito.

Unfortunately, the power surge of the TRPs apparently did not erase the original successful trip to the past, and Carlito is giving her an earful about throwing slushies on other customers and not letting her get a word in edgewise.  The two robbers then enter and move into the aisles of the store, and now she can't say anything.  Then, complicating her life further, Sebastian--younger Sebastian--enters.  He was expecting to meet her somewhere else, and wants to know why she's here.  She's trying to get him to leave the store and at the same time warn Carlito without tipping her hand to the robbers.  She grabs a pad and pen on the counter and writes a very brief note.

Carlito keeps a gun behind the counter, which he promptly grabs and aims it at one of the robbers, telling him he knows what they intend.  Unfortunately, both of the robbers have guns, and in a moment there is a stand-off.  Our view shifts to outside.  We hear gunshots, and then young Sebastian stumbles out of the bodega and collapses on the ground.  Time traveling Sebastian stares helplessly as Claudette races out, begging young Sebastian to live, but he doesn't, and as he dies time traveling Sebastian vanishes, his TRP and goggles falling to the ground.

Claudette grabs the gear and runs, returning to a future in which Calvin is now alive but Sebastian is dead.

We now come to a minor but critical piece of the story.  Sebastian's funeral has been held, and Calvin finds among Claudette's things a program for a funeral service with his, that is, Calvin's, picture on the front.  He wants to know what it is, whether it's a sick joke, and so forces Claudette to explain that she and Sebastian had invented time machines, that Calvin had been shot by police, and that when they went back to try to change that they saved Calvin but lost Sebastian.  She says she can fix it if she can go back in time again, but she needs help--and we'll get to that.

The problem is that program.  It doesn't exist in this history of the world, because Calvin was never shot.  Claudette can't have saved a copy of that program from the funeral that never was.

It might be thought that the program was protected, if perhaps Claudette took it with her when she traveled to the past.  Arguably, just as her memory doesn't change, her possessions don't change, either.  This won't stand, though.  Later she hands that program of Calvin's funeral to the younger Calvin just before the police force everyone to lie on the ground, and while he is lying on the ground he sees the picture and the name on the front of the program change from himself to Sebastian.  If it was going to change, it would already have done so in the timeline in which Sebastian's funeral replaced Calvin's.

The writers want it both ways.  They want Calvin to be able to see the program from his own funeral that Claudette had undone, but they also want him to see it change to Sebastian's when the tense situation suggests that it will be Sebastian who is killed.  They can't have that.  Either the program changes to Sebastian as soon as Sebastian's death replaces Calvin's and Calvin never sees his own funeral service program, or the program never changes and Calvin doesn't see it happen.

Claudette determines that she is going to return and save both Calvin and Sebastian.  It's not clear whether she has a plan, but she has pieces of a plan.  However, she needs the help of both Calvin and Eduardo, to get the one mostly functional TRP fully functional.

Eduardo contributes that if she tunes her TRP to the same frequency as her last trip, she will be able to replace herself.  It is not certain how this matters; thanks to Sebastian's notion of the higher quantum energy erasing the previous trip, this trip should remove her other self from the past just as that one did.  However, it gives the impression that with each trip they are refining the machine to work better.

That part of the plan appears to work, although Claudette arrives a few seconds later than the previous Sebastian, who wonders and asks why she was late.  She doesn't answer at that point, but instead drags him with her to try to avoid Jared and get to Calvin.  She has brought the program from Calvin's funeral, and Calvin has given her their father's dog tags which he never removed, even once telling her that she would be able to get them from him when he was dead.  She hopes that between the two she will be able to persuade the younger Calvin that she has come from the future and is trying to prevent him from being killed.

It's too big a concept for this Calvin to accept quickly.  He accuses her of forging copies of the dog tags and printing the program as a sick joke.  The four of them--Calvin, Dennis, Claudette, and Sebastian--are arguing in the street when the police arrive.

The police want to see identification, and the foursome are beginning to cooperate.  Unfortunately, Claudette mentioned the bodega robbery, and Dennis doesn't realize that this is something he couldn't know and so tells the police that they had nothing to do with that bodega robbery, which of course causes the police to conclude that they must have been involved if they know about it.  The four are ordered to lie face down on the ground.

From this position, Calvin can see the controller on Claudette's wrist counting down the remaining time for the wormhole, an uncomfortable Sebastian lying face down under the weight of his backpack, and the front of the funeral program sporting his name and picture.  He can see that the police are antsy, and they keep telling everyone not to move.  Then as he watches his picture fades and is replaced with Sebastian's.  Deciding that he can save Sebastian's life, he rises and is fatally shot by police.

Returning to the future, Claudette finds that Calvin is dead but Sebastian is alive.  Her mother has been hospitalized due to a nervous breakdown.  Sebastian is questioning her about why she changed a perfectly good plan, because this is the Sebastian who traveled to the past intending to call the police to stop the bodega robbery.  He realizes that she made a trip without him, and she bursts out that in that plan he died, and she had to save him.  He is horrified, and says that they have to stop, that time travel is too dangerous.  She repeats her belief that if she tries one more time she can make it work, and he shuts her down.

Apparently agreeing with him not to try again, Claudette prepares to follow him out of the garage.  Then once he is outside she closes and locks the door, grabs the TRP, and while he is scrambling in the house trying to find the keys to the garage she makes one more trip to the past.  We see her open the garage door and start running, and that is where the movie ends.

Along the right edge of this site is a list of movies that have already been analyzed; apart from the fact that movies in the same series or franchise have been kept together, they are listed in the order in which the analyses were written.  If I am counting aright, there have been eighty previous time travel movie analyses--so it's not surprising that some of the issues we find in any time travel film have been seen in some previous film, and for those who have kept pace with the site it must be at least a bit tedious to read detailed explanations of problems in a new film which were already addressed in an older one.  Thus I will attempt to address a couple of the more familiar problems briefly.

• Memory problems:  Each time Claudette goes to the past, with or without Sebastian, she changes history, but leaves a younger version of herself in the past who is unaware that a trip to the past was made or that there was an original history.  Yet when she returns to the future, she fully remembers the past she intended to change but not the past that was the consequence of it.  Where is the Claudette that lived through that new history?  Where are her memories?  We have seen this problem all the way back in Back to the Future and as recently as When We First Met, so it's a common problem, but it's an obvious flaw in time travel thinking.
• Reversion::  Another typically missed problem creating what we call an infinity loop, and have been talking about since the beginning of the site, a time traveler who erases the history from which he departs to the past must thereby erase his own departure and in doing so must similarly erase his own arrival.  In fact, anything that would prevent the same traveler from making the same trip for the same reason is likely to cause an infinity loop--but the ones in this film are a bit complicated.

  Claudette and Sebastian make a trip to attempt to save Calvin; they fail to reach him in time.  The next day, with the knowledge that that plan did not work, they devise a new plan, and again travel back to attempt to save Calvin by calling the police.  That plan also fails, but it has more serious consequences, because the younger Sebastian is fatally shot.

  This means that on July 9th when Claudette and Sebastian made that first attempt to save Calvin, they aren't going to make that trip.  Sebastian isn't going to make it because he is already dead; Claudette isn't going to make it because Calvin is alive, and this Claudette has no notion that Calvin was the one who was going to be killed.  As far as she knows, Sebastian stumbled into the bodega robbery and was shot.  She might attempt to travel back alone and prevent Sebastian from going to the bodega.  If she succeeds, though, then Calvin will be shot on a street some distance from the bodega, and Claudette and Sebastian will be attempting to save him on their July 9th trip.  We are caught in a loop.

  It should also be noted that Claudette made the trip to save Sebastian with Calvin's help, and now she doesn't have Calvin's help but Sebastian didn't die, so the trip of July 11th can't be made to save Sebastian because no one knows he would be shot in the bodega.  That also creates a loop.

• Pictures:  We already mentioned the changing funeral program.  This is a trope we denounced again in Back to the Future, although it doesn't appear that often.  The problem is amplified here, though, because the program did not change from Calvin to Sebastian in the history in which Sebastian died instead of Calvin, but instead changes when they have it in the past, in a history in which Sebastian might be shot again but then wasn't.  Such objects brought from a version of the future would retain their form until returned to the future, at which point if they never came into existence they never would have existed, and no one would have them.  Claudette can't have brought a funeral program with Calvin's picture on it to the past--and Calvin could not have found it in the future--because such a program never existed and so never came into her possession.  Yet if somehow she did have such a program, it would not have changed while Calvin was watching it, partly because the history from which it came had not yet been fully replaced, and partly because in the history they are creating Calvin will be the one killed.

When younger Sebastian dies on the sidewalk, time traveling Sebastian simply vanishes.  I can't think of another film right now that does that, but I know I've seen it, and objected that this wouldn't happen--this Sebastian traveled from a history in which he was not shot, and that history has not yet been fully erased, so he would remain here until he leaves for the future, never arriving in that future because he never departed from that future (yes, that infinity loop).  However, what amplifies this is that when he vanishes, his time travel gear--the pack and goggles and controller--fall to the sidewalk, left behind.

How is that even possible?

If Sebastian traveled from a future in which he is alive, he brought the gear with him, and as long as the gear is there Sebastian must be there, having brought it.  If Sebastian died in the past, then he never left from the future, and although having him vanish (suggesting that the future changes instantly when the past changes) is a bit ridiculous, if he never left from the future he never arrived in the past, and he didn't bring the time travel gear with him.  So even were we to accept the trope that the time traveler vanishes if his younger self is killed, anything he brought with him from the future, including the TRP, would vanish with him.

If we think otherwise, why are his clothes not in a heap on the sidewalk with the gear?

Probably they had the TRP land on the sidewalk because they wanted Claudette to take it back to the future with her, but this is also nonsense.  If she succeeds, the fact is that at the future end Sebastian never took that pack to the past because he was already dead, so she would have a temporal duplicate--the pack that Sebastian took to the past that she recovered, and the pack that he never took to the past.  One of those would cease to exist, and it makes the most sense for it to be the pack that was in the past, which should have vanished with Sebastian.

Calvin also vanishes from the alley in the future, and again we have the same issue:  he would not have been in that alley anyway, and in fact would have been buried by this point, so he is already gone.

At the end of the movie Claudette makes another solo trip, apparently believing that this time she can save both Sebastian and Calvin, and we are left with an interpretive enigma.

To this point, no matter what our time travelers do, someone they love dies.  In that sense, the film gives a feeling of inevitability, of fate or destiny, that the universe needs to claim a life from your closest circle now, and while you can choose which life that will be you cannot save all of them.  If we take that understanding, Claudette has condemned herself to becoming Sisyphus, fighting the unwinnable battle repeatedly like some Star Fleet cadet repeatedly trying to beat the Kobayashi Maru.  We can watch her running as the screen goes black and think that she is doomed to keep fighting against fate.

The other possibility is that this is about hope, that Claudette will succeed, if not this time then next time or the time after, that she will keep trying until ultimately she saves both Sebastian and Calvin.  We don't know what she plans to do differently this time, and it's possible she doesn't know either, but she is doing it, whatever it is.

Ultimately for the film's purposes, though, it doesn't matter whether she succeeds.  The point of the movie is in those words of Mr. Lockhart:  if you could travel to the past, what would you change?  The film gives us Claudette's answer:  she would do everything in her power to prevent her loved ones from being killed in shootings.