Pokémon 4Ever (劇場版ポケットモンスター セレビィ 時を越えた遭遇  Gekijoban Poketto Monsuta Serebii Toki o Koeta Sogu, lit. "Pocket Monsters the Movie: Celebi: The Meeting that Traversed Time") is the fourth official Pokémon movie. It was the first one to be distributed by Disney and the last Pokémon film to be released in wide theatres outside of Japan in 2002. The original Japanese version was released in theaters on July 7, 2001, and the English adaptation saw limited theatrical release on October 11, 2002.

The film focuses on Celebi who travels to the future with a boy named Sam when being chased by a hunter. Ash and his friends are on their way to the next gym of their Johto journey and get a lift from a man name Maki who takes them to his hometown of Arborville. The kids and Pikachu see a Suicune (who was actually the first Pokémon Ash saw in Johto). They are warned by an elderly lady about the "Voice of the Forest" which will carry a person off to a different period in time.

Ash and the group encounter the Voice of the Forest and find Sam in the forest, but Celebi has already fled. Sam awakens and discovers he has been on a 40-year journey in time. He, Ash and the others search for Celebi and they find it up in a tree. After some convincing, the gang manage to gain Celebi's trust. They run into Team Rocket and then another member of Team Rocket, the Iron Masked Marauder, who is after Celebi. The two forces of Team Rocket team up to search for Celebi.

The heroes take Celebi to its home, the Lake of Life, where it is healed by the water. The group spend the night in the forest. The next day, Celebi is captured and turns evil. The Iron Masked Marauder makes Celebi create a giant dragon creature made from the forest trees and Jessie is caught in the beast and held hostage. The heroes, and Meowth and James, chase after Celebi in Maki's flying boat, but are brought down by Celebi's attacks. The Iron Masked Marauder tries to kill Ash and Sam, but Suicune saves them. Onix and Suicune do battle with the Masked Marauder's Tyranitar, while Ash, Sam and Pikachu clamber into the monster and manage to get Celebi back to normal.

With the destruction of the monster, Jessie and the Iron Masked Marauder fall into the lake. The other heroes rush to the lake's edge and find Ash and Sam with Celebi, who suddenly falls limp. Ash and Sam realise Celebi is dead and everyone weeps. But then the Voice of the Forest materialises in the sky and thousands of Celebi appear and resurrect Celebi. The Iron Masked Marauder appears and kidnaps Celebi and tries to make a getaway, but not before Ash and Pikachu hitch a ride. Pikachu destroys the Masked Marauder's jetpack and they fall to Earth, but Celebi saves them. The Iron Masked Marauder falls down to the forest floor and is confronted by the old woman, her granddaughter and Maki.

Celebi prepares to travel back in time and Sam decides to go back with it. He has an emotional goodbye with Ash and departs. Later on, Ash and friends are talking with Professor Oak who tells Ash that he and Sam will be friends forever. Misty then realises that how can Oak know Sam's name? We then see Oak reflecting on the event, saying it seems like only yesterday.

The credits end with Tracey clearing Oak's room and finds Sam's drawing pad that has a faded sketch of Pikachu and Celebi in it.

From Wikipedia