After concluding his adventures in the Hoenn region, Satoshi sets off for Sinnoh to continue his quest to become a Pokémon Master. Upon arrival, Team Rocket's persistent scheme to snatch Pikachu fails yet again, leading to Pikachu getting lost in a dense forest. Satoshi must embark on a search to find his loyal companion. Along the way, he crosses paths with Takeshi, a seasoned Pokémon breeder and longtime travel companion, and encounters Shinji, a rival trainer driven by ambition and indifferent to his Pokémon's emotions. While on the hunt for Pikachu, Satoshi witnesses a powerful electric attack in the distance, prompting him to investigate and ultimately rescue Pikachu from Team Rocket alongside Hikari, an aspiring Pokémon coordinator. With Pikachu safely back by his side and Hikari joining their group, Satoshi and his friends kick off their thrilling exploration of the captivating Sinnoh region.