Ash, Pikachu, and their friends come to a desert city by the sea. Here they meet the Mythical Pokémon Hoopa, which has the ability to summon things—including people and Pokémon—through its magic rings. After a scary incident, they learn of a story about a brave hero who stopped the rampage of a terrifying Pokémon long ago. Now, the threat that has been bottled up for years is in danger of breaking loose again.
When the creator of the world, Arceus, comes to pass judgement on humanity for the theft of the legendary Jewel of Life, Ash and his friends are sent back in time to possibly reverse the events that led to Arceus' vendetta.
Ash and his friends must stop a greedy media mogul from using the shape-shifting Zoroark to capture the time-travelling Celebi.
