Ash and friends arrive on Mt. Coronet where Ash engages in a battle with a boy named Alan and his Nosepass. When the battle leaves the mountain, Alan says they must stay on the mountain in order for Nosepass to evolve. Eventually, Nosepass evolves into Probopass. Before the battle can continue, Team Rocket arrives and puts a device on Probopass, which turns it against Alan, and allows it to go with them. Team Rocket plans to make more controlling helmets in order to gain an army of Probopass. Meanwhile Ash and the others begin formulating a plan to get Probopass back.
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.