On the way to Pastoria City, Ash and his friends meet Tyler and his Piplup, Pippy. The pair is hot on the trail of a Yanma; Tyler's only been a Trainer for a week, but he's already spent three days trying to catch that Yanma! Ash and the gang help Tyler track the Yanma down, and Pippy battles it to wear it down. Now Tyler is ready to throw his Poké Ball and complete the capture—except Team Rocket slips in, nabs Yanma, and makes a quick getaway! Unable to find Team Rocket, our heroes can only cheer Tyler up and encourage him to find another Yanma to catch.

Team Rocket sends the purloined Yanma to Team Rocket headquarters, eagerly anticipating a reward from the Boss. But Team Rocket already has plenty of Yanma, so Giovanni sends it back without comment. Team Rocket thinks the Boss is just being generous, so Jessie takes charge of their new Yanma and sets out to catch another Yanma for Giovanni. It's not long before Team Rocket crosses paths with Tyler, who's just found another wild Yanma.

Jessie sends out her new Yanma, which evolves into a surprisingly tough Yanmega. Team Rocket is delighted by Yanmega's powerful SonicBoom and Ancient Power moves, except the fight with Tyler and Ash scares off the wild Yanma. Team Rocket might not have won this round, but Tyler is dismayed at losing out on another Yanma and Ash and his friends have to urge him not to give up. So when Tyler finds another Yanma and Team Rocket again shows up to spoil the show, Ash has Buizel and Pikachu put Team Rocket in their place. At last, Tyler catches a Yanma without any further interruption, and our heroes congratulate him before they resume their trip to Pastoria City.