When Alexa shows our heroes a mysterious treasure map linked to their next stop on Frond Island, everyone is very excited! She tells them the story of a pirate, his Pokémon (Shiftry, Nidoking, Mismagius, Honchkrow, and Vulpix), and the unknown treasure his ship contained. Jessie, James, and Meowth, who have been eavesdropping on our heroes’ conversation, decide to wait patiently until the Twerps find the treasure so they can steal it—and Pikachu too, of course...

Alexa takes Ash, Iris, and Cilan by boat to a small, deserted island nearby. After a narrow escape from a whirlpool, they find a hidden inlet that leads them through some tall cliffs as three Honchkrow keep a watchful eye on them. There, decaying on a beach, is a very old pirate ship! But Team Rocket has been following them underwater in a pedal-powered submarine, and when the villains surface too quickly, they ram the ancient ship by accident, sending it slithering back into the depths.

Ash is afraid the treasure went down with the ship, so he’s relieved when Alexa spies a door covered with symbols that resemble the ones on her treasure map! Cilan moves the symbols around to match the map, and the door opens to reveal a staircase.

At the top of the stairs is a dense forest, where our heroes are attacked by two Mismagius, then a Nidoking, and then three Shiftry! Alexa starts to put the pieces together and realizes that the Pokémon who have been attacking them match the story of the pirate and his crew! But they haven’t seen a Vulpix yet...

On the mountaintop, they find four Pokémon statues and one empty pillar. Then, the final Pokémon attacks—it’s a Ninetales, who must have evolved from the Vulpix they’ve been looking for! After they drive off the Ninetales, they discover the fifth statue and the secret entrance at its base. Sensing an opportunity, Jessie, James, and Meowth finally show themselves and prepare to battle our heroes for the treasure—but they’re all tired out from fighting the island’s Pokémon, and they’re quickly sent blasting off with nothing.

Sure enough, there’s a treasure chest inside the final statue, and it holds an amazing hoard of Evolution Stones! Our heroes and Alexa then realize the Pokémon that attacked them were protecting this treasure. Alexa decides to delete her records of this adventure, and everyone agrees to keep the island a secret, for the good of the Pokémon that live there. They return to the ship to continue their journey through the Decolore Islands and ultimately to Kanto!