Forty years ago, the Mythical Pokémon Celebi fled from a vicious hunter, and a young Trainer named Sammy rushed to protect it. Sammy and Celebi vanished in the forest—becoming yet another strange legend that the townspeople tell. In the present day, Ash and friends arrive in the forest, and find that the story is true when both boy and Pokémon turn up again! This time, the Iron Masked Marauder is after Celebi, armed with a cruel device that makes any Pokémon mindlessly obedient and evil. Can Ash, Sammy, Misty, and Brock withstand the power of the corrupted Celebi, and restore it to its true self?