The story starts at what is the end of Kes' life and goes backwards as she flashes through the various parts of her life on board Voyager, finding herself at earlier points along that life with each flash, gaining more memory as she continues along her journey. She finds out that she has been married to Lt. Tom Paris and had a daughter who in turn married Ensign Kim and had a child of her own. She also finds out that Voyager has been in a battle with a race called the Krenim during a time period called The Year Of Hell and that various crew members have died, including Captain Janeway and Lt. B'Elanna Torres. During one of the Krenim's attacks, an undetonated torpedo had pierced through Voyager and affected members of the crew with chroniton radiation, including Kes. It turns out that the machine the Doctor created near the end of Kes' life to help preserve it has activated the dormant chroniton particles in Kes' body, causing her backwards leap through time. At the present time, Kes gives the crew all the information they need to create another machine that would rid her body of all chroniton particles in order to put her back in sync with normal time. Although Kes experiences a few more jumps that take her back to the point of being conceived in the womb, the decontamination procedure in the present time proves to be effective, and soon Kes is back in sync with time, with only the memories of the crew's future.
This episode provides examples of:
- Back to Front: The story starts at the end of Kes' life and ends at the present time of Voyager's journey.
- Bad Future: Janeway, B'Elanna and Joe Carey are all killed during a year-long conflict with a hostile species. And less obvious at this stage in the series, eight years after arriving in the Delta Quadrant Voyager still hasn't returned home, and Seven and the Borg children are screwed.
- Back to the Womb: Exaggerated. As a result of her uncontrollable time-travelling, Kes not only goes back to being a fetus in the womb, but a zygote before she finally stops time-travelling.
- Be Careful What You Wish For: When Tom asks Kes about the future, Chakotay jokingly warns him that he might find out that he's destined to join a monastery.
- Big "NO!": Kes jumps back to the moment she joins Voyager's crew, and shouts "No!" as she feels herself time-shift again because it's her last chance to get help.
- Bizarre Alien Biology: Ocampan females give birth standing up, with the baby coming feet-first from a sac on their back. It is also established that Ocampan body temperature is a chilly 16.3 degrees Celsius.note
- Captain's Log: This time dictated by Captain Chakotay.
- Character Development: Obvious in pre-hair and post-hair Doctor — Doctor van Gogh is less hammy than his earlier self, with improved interpersonal skills and a (somewhat) restrained ego.
- Continuity Nod:
- After Kes blows out the candles on her birthday cake, Neelix says, "It's good to see that old lung is still working" referring to Season 1's "Phage" when Kes donated a lung to Neelix. The cake is a Jimbalian fudge cake like Neelix made for Kes' second birthday in "Twisted".
- In "Heroes and Demons" the Doctor said he'd narrowed his choice of a name down to three. He decides on Schweitzer in that episode, after the famous doctor, but decides not to continue using it. Presumably Mozart and Van Gogh were the other two.
- The Determinator: Kes never gives up trying to fix the problem.Doctor: Well you may have lost your memories, but you certainly haven't lost your determination.
- Dramatic Pause: "It's possible she might jump back to a time... before she even existed."
- Dying Declaration of Love (platonic): Just before an uncertain medical procedure that may or may not extend her life, the Doctor tells Kes she's the best friend he ever had and is embarrassed when Kes mentions this incident to his earlier self.
- "Eureka!" Moment: When Tom mentions the temporal flux of the chroniton torpedoes, he gets an idea of why Kes is travelling backwards through time.
- Explosive Instrumentation: An exploding console kills both Janeway and B'Elanna simultaneously. If that doesn't make Starfleet reinvent the fuse, nothing will.
- Foreshadowing: Meant to be an entire episode of this. In practice though, it foreshadowed many things that were planned at the time, but didn't end up happening, such as Kes living her entire life on Voyager, and the Year of Hell being an actual season, and not being retconned In-Universe.
- I'm Cold... So Cold...: Kes experiences this each time she's ready to make a time jump backward.
- Incest Subtext: Thanks to Bizarre Alien Biology — Tom is married to Kes, while his best friend Harry is married to their already grown-up daughter.
- It's a Long StoryKes: Doctor, you've lost your hair.Doctor: I beg your pardon?Kes: It's a long story.
- I Want My Beloved to Be Happy: Kes says nothing to Tom about them being married in the future when she sees him kissing B'Elanna, nor does she mention to either person that they'll be an Official Couple in future when she returns to the present.
- Married in the Future
- Maternity Crisis: Exaggerated when Kes jumps back into her earlier body just as she's giving birth on a shuttle that's about to dock with a severely-damaged Voyager that's under constant attack.
- The Main Characters Do Everything: It's far-fetched enough to believe that, out of a ship of a hundred-and-fifty, the only romantic options for Kes and Tom after Neelix and B'Elanna respectively were each other; but then, of all the men aboard, their daughter marries Harry Kim. And then there's Neelix, who is implied to have become chief of security after Tuvok's promotion in the wake of Janeway's death. Apparently in that timeline, the Year of Hell took out Ayala, Andrews, Baxter, and all other runners up for the job. (Admittedly, the former three are not seen in this episode...) It's also quite far-fetched that Kes - who is just about to give birth - will be allowed to go on a supply run, in which only Tom was supposed to go. Especially with Tom and Kes being the only two medics on Voyager with the Doctor offline, during the Year of Hell!
- Mayfly–December Romance: At 9 years old Kes is elderly and nearing the end of her life. She is married to Tom who has only aged 8 human years and thus looks pretty much the same as usual. Tom and Kes' daughter has already grown up and married Harry.
- Merlin Sickness: Only instead of aging backwards as Kes is going forward in time, she's just going back in time and de-aging while gaining knowledge with each jump.
- The Nameless: Averted; the Doctor now calls himself Van Gogh. After previously deciding on Mozart.
- Oh, Crap!: Kes has gathered enough information so the Doctor can treat her, only to start rapidly time-jumping back to her childhood, her birth, and eventually a fetus!
- P.O.V. Cam: Done at the beginning of the episode.
- Reset Button: Kes is stabilized at the current point in the series — although her Scifi Bob Haircut has been replaced by a longer hairstyle, implying some passage of time since the events of "Favorite Son".
- Ret-Gone:
- Technically the case with Linnis and Andrew, though no one ever comments on it.
- The crew discovers Kes's backwards jumps through time while Linnis and Andrew are still present, but no one considers the impact her time traveling might have on her daughter or grandson.
- Kes likewise doesn't hesitate to warn Janeway about the Krenim the moment she has the chance, expressing no conflict over the fact that this is effectively erasing Linnis and Andrew. Even when discussing the future she saw with the crew at the end, and Tuvok reminding her that her actions likely changed it, she expresses only relief. Maybe Harry marrying Linnis just squicked her out that much.
- Second Law of Metafictional Thermodynamics: Though this is used to set up the Alternate Timeline — Janeway's death means Chakotay is captain, and B'Elanna's death means Tom hooks up with Kes.
- Separated by the Wall: Tom reaches for Kes as she vanishes back in time, but she's stuck behind a medical forcefield.
- Snark-to-Snark CombatNeelix: I haven't made [a cake] since I became Security Officer.Tuvok: Perhaps you would care to relinquish your commission, and return to the scene of your 'former' triumphs.Neelix: You just keep working on that sense of humor, Commander Vulcan. You'll get it one of these days.
- Techno Babble: Modulating the targeting sensors to a parametric frequency. Whatever it means, it comes in handy when Kes remembers it after another time-jump.
- Time Travel
- We Are as Mayflies: The episode starts with Kes as a nine year-old grandmother, undergoing a medical procedure to extend her life another year.
- What Year Is This?: Kes is frequently confused by the year when she jumps back in time.
- Wham Line: When Chakotay first appears he's addressed as "Captain".
- You Have to Believe Me!: Everyone thinks Kes is ill until she jumps back in time to before the Doctor told her about his intended treatment. The further she goes back in time, the more data she collects so it's easier to convince people...until she ends up an Ocampan child again.
- Your Favorite: The Jimbalian fudge cake Neelix makes for Kes' ninth birthday.
