Giratina, the legendary Renegade Pokémon, confronts Dialga, the Temporal Pokémon, at a lake. Giratina successfully transports Dialga to a different dimension, leaving behind an unintended green Pokémon who evades capture. Dialga manages to escape while Giratina is busy chasing the little green creature. During Satoshi and his friends' outdoor feast, the green creature accidentally disrupts their gathering. They take it to the Pokémon Center for medical attention and discover that it's Shaymin, the mythical Gratitude Pokémon, who can communicate telepathically. Shaymin insists on being taken somewhere but doesn't reveal the desired location. As they search for Shaymin's destination, they encounter danger from Giratina and Zero, who are both pursuing the valuable Pokémon. Will Satoshi and his friends evade danger and help Shaymin find its desired location?