Ash's newly caught Treecko may be a bit standoff-ish, but the little green Pokémon is quite a fighter. When Team Rocket sees Treecko knocked down and hurt by a Seviper, they decide that they must have that Seviper. Jessie is very impressed with its "sneaky, snakey ways."

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.