Ash, Misty, and Brock walk along Palmpona's waterfront admiring the sea view. They see a young Trainer instructing his Wobbuffet to stand up straight. Ash looks Wobbuffet up on his Pokédex and the boy introduces himself as Benny. He says that he is going to the Pokémon Swap Meet to find someone to trade his Wobbuffet to. Misty wonders why he would want to trade his Pokémon and Benny says he likes Wobbuffet and has trained him hard but now he wants a different Pokémon.
Meanwhile, James waters his Victreebel with a hose while Jessie uses the public taps to clean her face, only to be licked by her Lickitung immediately after. Meowth tells his teammates about the Swap Meet event, and the trio set their sights on stealing some Pokémon, but, unbeknownst to them, Snubbull is following them.
The group reaches a town square when a herd of Tauros comes running by. One of the bystanders explains that it is the "Running of the Tauros" event, and to win a trophy from the mayor, a competitor must touch a Tauros horn. Ash attempts to join the event, but gets scared and moves out of the way. All of the Tauros run into a stadium and begin a huge battling competition. Still intent on participating, Ash calls Professor Oak, and at his request, he exchanges his Heracross for Tauros. The announcer declares that Fernando has defeated ten opponents and just before he is about to be declared the competition winner, Ash jumps from the stands and challenges him. The two Tauros exchange Take Down attacks and the pair appear to be evenly matched. Fernando's Tauros begins to push Ash's Tauros, but after another Take Down, Ash is declared the winner of the competition.
Afterward, Benny, who watched the show of strength, tries to find Ash to trade his Wobbuffet for Ash's Tauros. However, several other Trainers had the same idea and soon swarm around Ash. They offer him offering him trades, but Ash says he could never trade his Tauros. Benny realizes that Ash would never trade one of his Pokémon away. Benny tries to find a trade partner, but with no luck. Ash and Brock come along and decide to help him. As Misty walks around, her Psyduck makes an unannounced appearance. Immediately several Trainers offer her potential trades for it, but Misty considers that Psyduck might have some value and declines. Ash and Brock manage to negotiate a deal with a Trainer for his Stantler, promising to give him a warranty when he receives Wobbuffet.
James walks around, with some money in hand from the snacks the trio sold earlier, and comes across a Magikarp salesman. Just as James agrees to buy the bargain Magikarp, he remembers the salesman, but the salesman manages to run off with his money. The man with the Stantler abandons the trade with Benny at the last minute after spotting a Hoothoot. Meanwhile, James chases after the salesman, Jessie gets in the way and is sent flying towards the real trading machine. Jessie falls and hits her head on the machine as the Poké Ball containing Lickitung flies out of her pocket and lands on the machine. The Poké Ball exchanges with Benny's but Jessie isn't looking. She grabs the Poké Ball and runs off.
Team Rocket's latest scheme, a fake trade machine that swaps full Poké Balls for empty ones soon falls through. People have started to suspect that the machine is a fake so Team Rocket reveals themselves and ties everyone up. Team Rocket then jumps into their balloon and begins to float away with their loot. James then clicks a button and begins to vacuum up everyone's remaining Poké Balls. At Ash's command, the Trainers call out their Tauros and Take Down Team Rocket. The force causes Team Rocket to burst their own balloon and blast off, leaving the sack behind. A Trainer uses his Scyther to free everyone. Then, the Trainers open the sack, only to find more empty Poké Balls. Ash and friends go to find Team Rocket and retrieve the stolen Pokémon.
Soon enough, Ash's group locates Team Rocket and a battle ensues. Ash sends out Chikorita and Jessie calls on her Lickitung, but she is shocked to see her new Wobbuffet appear instead. Ash is confused by Team Rocket's latest addition, but Jessie soon remembers that it must have occurred when she bumped into the trading machine. Jessie is irritated but commands Wobbuffet to attack, but James then reads his book and reveals that Wobbuffet cannot initiate an attack. Chikorita hits Wobbuffet with a Vine Whip. Ash follows up with another Vine Whip and Razor Leaf, but Wobbuffet uses its powerful Counter and knocks Chikorita out. Jessie is immediately impressed with Wobbuffet’s performance as James and Meowth cheer it on. Ash then sends out Pikachu who uses a Thunderbolt, which Wobbuffet cannot Counter due to it being a special attack. This subsequently sends Team Rocket blasting off, leaving the Poké Balls behind.
Back at the Swap Meet, the gang returns the Poké Balls to the Trainers. Benny runs up to them with his new Lickitung, and he is happy and seemingly enjoys its affectionate habit of licking his face. He explains that he was able to trade Wobbuffet to a lady but she ran off and he can't find her to thank her. The gang, not piecing together that Benny actually traded with Jessie, thinks she must have gone home for the day. Benny calls out to her to thank her and asks her to take good care of Wobbuffet.
Meanwhile, Team Rocket hangs on a branch with Wobbuffet as they realize that, no matter how it happened, they have a new member. Meowth tells Jessie she'll have to look after Wobbuffet now, as she despairs over having gotten such an unusual Pokémon.