Ash and the others return to Jubilife City, needing to go through the town to get to Floaroma Town. The end up at the headquarters of the B Button League, a group of people who want to get their pokémon to be strong and beautiful without evolving them, as well as their leaders, Haley and Oralie. Meanwhile, the Magikarp salesman once again swindles Team Rocket. This time he gets them to buy a machine that will force Pokemon to evolve. Ash decides to battle Oralie, and she will be using her Magikarp. Despite being at an advantage with Pikachu, the Magikarp still beats both Pikachu and Piplup! After seeing Magikarp's power, Team Rocket decides to steal Magikarp and Feebas and force them to evolve, giving them a powerful Gyarados and a beautiful Milotic, not to mention they also steal Pikachu and plan to evolve it into Raichu. Now, Ash and the others must get their Pokemon back before Team Rocket makes them evolve, and ruins all their hard work.
A young boy named Ash Ketchum embarks on a journey to become a "Pokemon Master" with his first Pokemon, Pikachu. Joining him on his travels are Brock, a girl-obsessed Rock Pokemon Trainer, and Misty, a tomboyish Water Pokemon Trainer who may have a crush on him. Ash and Co. end up traveling through various regions, including Kanto, the Orange Islands, and Johto, and then enter the Pokemon League competitions there.
Along the way, they run into many confrontations with Jessie, James, and Meowth, a trio of Pokemon thieves who are apart of an evil organization called "Team Rocket". But every time Team Rocket try to do their evil deeds, they fail thanks to Ash and his Pokemon.