Nurse Joy of Rinshin Town

Ash and his friends arrive at an unofficial Gym, where, according to a billboard, it houses the world's most powerful Pokémon. Unable to pass up a challenge, Ash decides to challenge this Pokémon. As the gang arrives to the Gym, a Trainer is rushing his way out of there; stating with frustration that the Pokémon in question wasn't normal at all, making Ash's desire to defeat the world's most powerful Pokémon grow even bigger. As he makes his challenge, a Trainer named Anthony arrives to accept the challenge, along with his Pelipper. The rules of the battle are simple: Anthony will only use his Pelipper, while Ash may use as many of his Pokémon as he wished. Ash decides to lead off with Treecko against Pelipper. The battle unfolds normally, with Pelipper using Wing Attack, to which Treecko dodges effortlessly, but then Anthony suddenly tells Pelipper to use Vine Whip, which, as Max points out, Pelipper cannot learn (as he contends that Pelipper can only use Water and Flying-typeattacks), but sure enough, a pair of vines manage to come out of Pelipper's mouth and trip up Treecko. Max becomes suspicious of Anthony's battling skills, while Ash is forced to withdraw Treecko forTaillow. Taillow seems to handle the battle pretty well and tries to attack with Peck, though, Anthony makes another suspicious move and orders Pelipper to use Flamethrower, which hits Taillow and knocks it out, much to the amazement of everybody (especially Max, who can't believe that Pelipper is able to use Fire-type moves.) Ash is down to Pikachu, who he warns to expect the unexpected. Sure enough, when Pikachu uses Thunder, Pelipper is directed to counter with its own Thunder, once again making Max suspicious. However, Pikachu manages to draw even against Pelipper.

Meanwhile, Team Rocket is plotting to steal the Pelipper, and, as they put their plan into motion, they manage to make a Bellsprout fall from Pelipper's mouth as Anthony tries to defend Pelipper withWater Gun, Flamethrower, and Thunderbolt at the same time. Team Rocket learns of Anthony's "winning ways": Pelipper could perform the attacks because its mouth housed a Bellsprout, a Magby, and a Magnemite; and blackmail Anthony and Pelipper to cooperate on their latest Pokémon-stealing scheme.

At the Pokémon Center, as they are waiting for Ash's team to heal, Max is convinced that Anthony is cheating somehow, while May dismisses it as real-world not matching up with Max's book-smarts. When Trainers begin to pour in saying that their Pokémon have been taken by the world's most powerful Pokémon, Ash cannot believe that Anthony would stoop so low as to steal their challenger's Pokémon, though Brock suggests that Anthony had been coerced. Sure enough, when they arrive at the Gym, two promoters (Jessie and James) are promoting a challenge where challengers have to ante up a Pokémon against Pelipper, with the winner taking both Pokémon. As Ash accepts the challenge again to get to the bottom of the situation, starting with Pikachu; Jessie and James become worried, as Pikachu has beaten them numerous times before. As a precaution, Jessie and James load up more Poké Balls inside Pelipper, and then puts Meowth inside Pelipper as a "tactical controller".

As the rematch begins, Pelipper starts with Bellsprout's Vine Whip, which Pikachu manages to dodge. Meowth, inside Pelipper, then switches to Magby for a SmokeScreen, which soon finds its way into Pelipper's mouth, affecting both Meowth and Magby in addition to Pikachu. As Meowth brings back Bellsprout for a Razor Leaf, Max wanders off and manages to find Anthony, bound and gagged, who confesses to having cheated by hiding Poké Balls inside Pelipper's mouth. Meanwhile, Meowth comes up with a plan to take down Pikachu: after dowsing it with a Water Gun, it can switch to Magnemite and fire off Thunder to deal more damage to a wet Pikachu. Because he cannot find any stowed Water Pokémon, Meowth chooses to instead use Pelipper itself to fire the Water Gun, but as he does so, Pelipper shoots water everywhere - at not only Pikachu, but Ash, Brock, May, Max, Anthony, Jessie, and James as well, exposing Team Rocket and the Poké Balls (and Meowth) inside Pelipper's mouth. As Team Rocket tries to make their getaway with the stolen Poké Balls, though, they are countered by Pelipper using Wing Attack to free their Poké Ball bag. When Team Rocket tries to take Pikachu as a last resort, Pelipper uses Water Gun to soak the balloon, allowing Pikachu to Thunderbolt through Team Rocket's electricity-proof suits, sending them flying.

The episode ends with Anthony closing up the Gym, and deciding to go straight with Pelipper, as Pelipper was powerful even without the Poké Balls in its mouth.