The gang arrived to Wazoo Island. The island is known for its beautiful beaches (and to Brock, beautiful girls as well). Suddenly, a man (engulfed in sea weed) arrives, saying that Adam (he) got finally the treasure! The treasure are gems - emeralds. Adam goes to show the gang his shop, introducing to them his wife. The woman examines that they are green shards, actually - worth more than what he caught before. Adam thinks that the shards are from a ship named King Neptune - once its cargo (and the ship) was lost to a storm. The crew within got out alive, but a tale goes that Neptune got the treasure beyond everyone's thoughts.
Adam remembers that before he went out of the sea, he saw a Relicanth carrying the green shards - it dropped them and gone away, leaving Adam to pick them up. Brock suspects the Relicanth and the shards might have a connection. Adam and his wife plan to get to that ship. Team Rocket overhears their plan, so they also plan to get the treasure first. Jessie and James think what they'll do with the treasure, but Meowth thinks they should give it to their boss instead. Somewhere at sea, the woman releases Adam and the gang in a small submarine to search the ship. The deeper they go, the darker it is, so Adam switches the lights on, revealing some Water Pokémon.
Suddenly, Adam sees something on the sonar, so goes to get to the spot. It is a Relicanth, however, they are attacked by Team Rocket's Magikarp submarine. Jessie complains they need to work to get the submarine going, so James sends Chimecho to improve their morale. Meowth releases some missiles, damaging the other submarine. Adam gives report to his wife via the intercom. Team Rocket follows the Relicanth, but suddenly they see leakages. Jessie wants still to continue. However, they got swept away by the underwater current. The gang spots an underwater cave, so they follow the current. Adam's wife loses the contact. The submarine is lost to darkness.
Adam wakes the others up and everyone is fine. They spot the giant ship, seeming to be the one from Adam's tale. The cave has fresh air, unusually. They spot a giant opening, so it must be where they have gone from. Many Relicanth appear from the ship. Adam comes with a chest. He goes to open it, but Team Rocket arrive to take the chest. They get the chest and release the missiles, damaging the ship. As they are to go back to the submarine, Relicanth appear (very angrily looking). Jessie releases missiles to hurt the Relicanth, but Ash sends Corphish, using Bubble Beam in time to destroy the missiles.
Team Rocket goes away and release the missiles, blocking the gang's path. The Relicanth go to another path, so the gang enters the submarine and go follow the Relicanth. Adam's woman, Evelyn, tries to make contact, so finally Adam responds. Adam and the gang go to Evelyn's boat. Adam tells her that they lost the treasure chest, so Evelyn tells him that she tracked them down. Team Rocket is seen on a beach with the chest. The gang appears on Adam and Evelyn's boat, demanding back the treasure and amazing Team Rocket as to how they escaped the cave. May sends Bulbasaur and uses Vine Whip to get the chest, but Team Rocket grabs it. Jessie sends Seviper and uses Poison Tail on Bulbasaur.
Brock sends Mudkip and uses Water Gun, along with Relicanth who use Hydro Pump on Team Rocket. Bulbasaur takes the chest and Pikachu attacks them with Thunder, blasting them off. Adam opens the chest and they see - green shards. Brock thinks that green shards were more worth than emeralds, back then anyway. Evelyn cheers him up, as they can use it for jewelry. Adam gains confidence, as there are many things he did not yet encounter. He wishes good luck for Relicanth to get a new home.
- Featured Pokémon: Remoraid, Octillery, Carvanha, Mantine