A long time ago, a little forest guardian known as Celebi is chased by an unknown Pokémon poacher. A young Trainer, Sam, saves Celebi, and the two travel through time. In the present day, a member of Team Rocket, known as the Iron Mask Marauder ("Vicious" in Japanese), confronts the now old poacher and destroys his home, taking a Tyranitar with him.
Ash, Misty and Brock see a Suicune, and Oak tells them about the legendary Pokémon. While in the woods, they see Sam, and they befriend him. Unfortunately, the Iron Masked Marauder plans to capture Celebi for himself, and he plans to overthrow Giovanni in the process.
The movie provides examples of:
- Adaptation Expansion: Or in this case a dub expansion. 4Kids had the Japanese animators create additional scenes to make it more clear that Sammy is Professor Oak.
- Adapted Out: Tracey makes two appearances as Oak's assistant. Both scenes were removed in the dub version, reducing his presence to a cameo during the end credits.
- All Just a Dream: In the Japanese version, Sam wakes up after being returned to the past and mentions he had "a wonderful dream." In the dub, this isn't the case.
- Big Bad: The Iron Masked Marauder.
- Big Damn Heroes: Suicune.
- Blatant Lies: This exchange during Ash and the gang's first encounter with the Marauder as he blocks their way on his spider-bot.Iron-Masked Marauder: I've been lookin' for that little Celebi!
Ash: Who are you?
Iron-Masked Marauder: A Pokémon lover.
Ash: Leave us alone!
- Brainwashed and Crazy: Dark Celebi. Same goes for any Pokémon caught in a Dark Ball.
- Broken Aesop: The movie's Deus ex Machina ending is why Linkara hates the movie so much, as pointed out in his crossover review with That Dude in the Suede. Why bother bringing up the danger of permanently wrecking the environment when they make the whole thing crash and burn by bringing the once dead Celebi back to life?
- Call-Forward: Sammy's sketching hobby, considering it might be the inspiration for the Pokédex, and that Sammy's "biggest fan" (currently his assistant) has the very same hobby.
- Captain Obvious: Brock, as always:Brock: (after the water from the Lake of Life turns Celebi healthy again) This must be the Lake of Life. ...Hey, that's it! The lake water must have brought Celebi back to life!
- Chekhov's Classroom: The conversation with Professor Oak at the start of the movie. He mentions Suicune's ability to purify water, as well as his claiming that he only saw Suicune just one time.
- Conspicuous CG: Most notably in the scene where Suicune makes its first proper appearance and with the giant twig monster Celebi creates.
- A Day in the Limelight: Professor Oak, even though we don't know it at the time.
- Deus ex Machina: Just when all hope of reviving Celebi seems lost, the Celebis of past and future suddenly appear and do it.
- Disney Death: Celebi.
- Disney Villain Death: Subverted, to rather ridiculous levels. The Marauder falls several meters, lands in a tree branch that snaps and then lands and rolls down a small hill, finally landing hard on the ground. Then Diana, Toya, and Mr. White along with the angry forest Pokémon confront him. The now powerless Marauder begs for mercy, claiming: "This is all a mistake a big misunderstanding!" Then Caterpie, Weedle, and Spinarak spray silk at him tying him up to which Toya responds: "I think the Pokémon understand perfectly!"
- Distressed Damsel: Jessie becomes one.
- Eldritch Abomination: Whatever the hell Celebi makes out of the chunks of forest it decimates. It has spider legs, horns, skeletal wings, and can blast the crap out of about half a mile of tree canopy to vaporize half of the lake on the other side.
- Even Evil Has Standards: Jessie, James and Meowth initially accompany the Marauder to catch Celebi (out of fear of him). However, they're genuinely horrified of the Marauder's methods in doing so (i.e. brutally electrocuting Celebi, and brainwashing it into destroying the forest). The trio may love stealing Pokémon, but they would NEVER sadistically torture and manipulate them!
- Jessie is also horrified when the Marauder tells her that he plans to use Celebi to overthrow Giovanni and rule Team Rocket.
- Everything's Better with Sparkles/Everything's Better with Spinning: Celebi is trailing sparkles and spinning when it pops out of the Lake of Life completely healed and when it heals Misty's twisted knee.
- Eye Scream: The hunter who attempts to capture Celebi at the beginning of the movie has an artificial eye in place of his right one.
- Fish out of Temporal Water: Sam travels from the past to the present day.
- Fingore: The Iron-Masked Marauder manages to knock Ash unconscious by painfully stepping on his fingers when he retrieves Celebi's Dark Ball.
- Genki Girl: Celebi, if seen as a girl. She is very hyperactive.
- Getting Crap Past the Radar:Brock: (to Diana) Why don't you come too, and protect us?
Misty: Then she'd need protection. From you.
- Made even worse by the other definition of "protection."
- Most likely an accident, but for those at home who have the DVD, look at the back cover, mainly at Misty. She appears to have no pants on.
- When the Marauder blows up the hunter's camp, the hunter begs for mercy while clinging to the Marauder's...crotch. Additionally, scattered around his room are what appear to be empty wine bottles.
- A God Am I: The extent that the Marauder believes of just how powerful he considers Celebi will make him.
- Green Thumb/Psychic Powers: Celebi.
- Humongous Mecha: The giant spider robot four legs thing that the Marauder uses to try and capture Celebi.
- I Never Told You His Name: In the final scene, the gang tells Professor Oak about their most recent adventure and Professor Oak notices Ash is unusually subdued. Ash tells him about the boy he befriended who went back to his own time and how Ash is worried they'll never meet again. Professor Oak reassures him that true friendships stand the test of time and that "I'm sure you and Sammy will be friends forever." After the video call is over, Misty realizes they never mentioned Sammy's name to the Professor... Cut to Professor Oak in his lab looking through his old sketchbook and saying, "It seems like it happened only yesterday."
- Lighter and Softer: Than the past three films...until the climax, that is. See Nightmare Fuel in the YMMV page.
- Missed the Bus: Ash narrowly averts this in the opening credits, with a boat that he didn't board earlier because he was in the middle of a Pokémon battle. He ends up having to make a leap for it.
- Nature Spirit: Celebi, though Suicune also shows off its ability to purify water in this movie.
- Never Say "Die": Averted in the English dub. Sam specifically says "Now it's too late to choose because Celebi's going to die!"
- No-Sell: A Dark Ball can catch a Pokémon that was already in the possession of someone else.
- The Old North Wind: Suicune, a veritable Nature Spirit, is referred to by several characters as "The North Wind".
- Paint It Black: Whenever a Pokémon is caught by a Dark Ball, their skin color darkens.
- The Reveal: At the end, it’s heavily implied that Sam is Professor Oak.
- Ridiculously Cute Critter: Celebi.
- Saying Too Much: In one of the 4Kids added scenes, Misty realizes how strange it was for Professor Oak to know Sam's name, even though Ash never mentioned it.
- Schizo Tech: The past that Sam comes from is pretty inconsistent in tech level. On one hand, Poke Balls from that time period need to be wound-up before use. On the other hand, a poacher from that period has a cyber eye and electro trap, while riding a fairly old motorcycle.
- Shout-Out: There's a trainer who's named Dundee in the English dub. He's got a Croconaw. He's also got an Australian accent.
- Sleep Cute: Pikachu and Celebi. Awww.
- Stable Time Loop: See Timey-Wimey Ball.
- The Starscream: The Marauder was planning on being this by using Celebi's power to take over Team Rocket. Fairly small goal with the power of a time traveling legendary.
- Stuff Blowing Up: At the beginning of the movie, the Marauder uses Dark Tyranitar to blow up the old hunter's ranch to make him say where he found Celebi.
- Time Master: Celebi can travel through time.
- Timey-Wimey Ball: Sammy's identity has become ripe planting ground for Epileptic Trees regarding the series, some bordering on Fridge Brilliance and/or Fridge Logic.
- It's also questionable whether the many Celebi that appear to heal the main one at the film's climax are different members of the species or the same one from different points in time.
- Title Drop: A case can be made regarding Professor Oak reassuring Ash that, in spite of Sammy travelling back to the past, he and Ash will be friends "forever."
- Villainous Rescue: Of a sort, since the Terrible Trio aren't the main antagonists here, but Jessie grabbing onto Ash and Sammy when the two boys are flung against the Eldritch Abomination could still count. Bonus points for Jessie being a Damsel in Distress herself at the time.
- Whole Plot Reference: This movie's plot — particularly Celebi becoming evil, giving rise to a monster that destroys the forest, being killed and coming back to life — is supiciously similar to that of Princess Mononoke.
- Would Hurt a Child: The Iron-Masked Marauder. Not only does he order Dark Celebi to "get rid of" Ash and his friends, he also tries to kick Ash away from him while they are a considerable distance off the ground.
- You Have Outlived Your Usefulness: The Marauder's attitude when seeing Scizor and Sneasel tied up. He just leaves them there without a care and continues to pursue Ash and Celebi. His decision comes back to bite him on the ass after he loses all his weapons and left at the mercy of the forest Pokémon.