On their way to the Whirl Cup competition, Ash and friends are fortunate enough to pass a small mountain village just as an annual Chinchou migration is about to occur. When both a vicious rainstorm and Team Rocket threaten the travel to the Chinchou's breeding grounds, Ash and friends must help Dayton and his father keep all the Chinchou safe.

While trying to find a ride to Red Rock Isle, Ash and friends meet a girl named Luka. After learning about how she is trying to find a treasure on the bottom of the ocean nearby, Ash and friends decide to join her on her quest