Following his journey in the Johto League, Satoshi decides to embark on a new adventure with Pikachu in the mystical region of Houen. However, he doesn't tread alone for very long as Haruka, a 10-year-old who harbors an aversion to Pokémon but has a keen desire to explore the world, joins him after Pikachu unintentionally wreaks havoc on her bike. During his expedition, Satoshi reunites with his former travel companion Takeshi and meets Haruka's younger sibling Masato. As a team, they traverse through Houen, engaging in battles against Gym Leaders, participating in contests, and experiencing various other events en route to achieving victory in the Houen League.