A treasure-hunter startles Ash and friends as he emerges suddenly from the sea, boasting of what he believes to be his first great underwater find. Excited to help uncover any Pokémon mystery themselves, our heroes quickly volunteer to join in the excavation, guided by the ancient Pokémon, Relicanth, which this diver insists will lead them to riches. Not to be outdone in greed, Team Rocket follows close behind, watching for the perfect moment to attack as their young nemeses bravely swim deeper into the sea.