It’s the first day of the Twinleaf Festival, and Professor Oak is scheduled to give a lecture on “the interrelation of Pokémon and Evolutionary stones.” But a flat tire forces him to make a stop near a marshland, where he discovers a wealth of Pokémon! While there, he helps one of the Pokémon, a Lombre, evolve into a Ludicolo using a Water Stone.

Meanwhile, Team Rocket has decided that a great way to capitalize on the upcoming lecture is to sell Oak memorabilia—with James dressed up as the spitting image of Professor Oak to do the selling!

While waiting for Professor Oak to arrive, the festival committee—that is, Johanna, Izzy and Cara—mistakes James for the real Professor Oak and drags him to the lecture. Jessie and Meowth secretly convince James it’s a golden opportunity to steal the audience’s Poké Balls! Suddenly the real Professor Oak bursts in with Ash and friends, and everyone must figure out who in fact is the real Professor Oak...

But an ailing Tyranitar sends James blasting off again, and the real Professor Oak heals the Tyranitar by removing a thorn from its foot. This leaves the hapless Team Rocket with no Poké Balls, which proves who the real Professor Oak is!