On their way through the Battle Frontier, Ash and friends meet up with a Pokémon Ranger who's mission is to deliever the egg of Manaphy to a temple on the ocean's floor. However, a greedy pirate wants the power of Manaphy to himself.

It all started with a legend passed down from the people of the water

On their way through the Battle Frontier, Ash and friends meet up with a Pokémon Ranger who's mission is to deliever the egg of Manaphy to a temple on the ocean's floor. However, a greedy pirate wants the power of Manaphy to himself.