En route to Rustboro City, Ash and the gang pass by an unofficial gym boasting the world's most powerful Pokémon. Even though he can't win a badge there, Ash is intrigued and decides to battle the trainer named Anthony and this mysterious Pokémon.

Ash and friends are relaxing in a lake when they come across a group of Lotad. The Lotad help a group of three sisters grow flowers and berries for their shop. The runt of the Lotad litter is having trouble, though, and Brock gives it some advice and encouragement. Natalie, the youngest sister, develops a crush on Brock and runs off to find a Sitrus Berry to give him. Brock and company arrive just in time to save her from a wild Beedrill. But just then, Team Rocket sets out to catch all of the Lotad in the lake. Pikachu joins forces with the lake dwellers to stop Team Rocket, and afterward, the littlest Lotad decides to join Brock as his Pokémon!