Ash and friends are finally on their way to Lily of the Valley Island. On the boat ride to a nearby island, they meet a trainer named Buck. Buck plans to get off at the next island in order to search for a special treasure said to be located on the island. Intrigued, Ash, Dawn, and Brock decide to join Buck on his adventure. However, treasure hunting won't be easy when the island is guarded with various groups of Pokémon.