A magician attempts to use the power of the Millennium Comet to awaken the legendary Pokémon Groudon.

Ash, Pikachu and the rest of the Pokemon gang try and stop a pair of thieves hiding out in the canals and alleyways of Alto Mare, the water capital of the world. Joining the adventure are two new Pokémons, a brother/sister pair named Latias and Latios who are protecting the Droplet of the Heart - a valuable treasure.

Yugi, a smaller than average high school student, and an easy target for bullies, is given an ancient Egyptian riddle called the "Millennium Puzzle" by his grandfather, a local game shop manager. Yugi pieces the puzzle together and unexpectedly becomes the powerful "Game King." Now when Yugi gets into sticky situations, the "Game King" takes over and protects Yugi and his friends.