Pokemon Diamond & Pearl

Ash Ketchum travels to the Sinnoh region after completing his Hoenn journey, aiming to become a Pokémon Master. He's soon reunited with his old friend Brock, a Pokémon breeder, and meets Shinji, a fellow trainer who's more focused on winning than Pokémon welfare. While searching for Pikachu, who's gone missing in the forest, Ash encounters Hikari, a Pokémon coordinator novice, and foils Team Rocket's attempt to capture Pikachu with her help. Hikari eventually joins Ash on his journey in the Sinnoh region.