Chase is a young boy from Pallet Town. His adventure begins one day when Professor Oak calls him and his friend, Trace to his lab for a starter Pokémon. Chase picks a Pikachu or Eevee, while Trace picks the opposite Pokémon. Oak also gives them each a Pokédex with which to record data on all known Pokémon in the Kanto region to fulfill Oak's dream of creating a full guide on all Pokémon in Kanto.
From here, Chase and Trace journey across Kanto, collecting Pokémon to build up their teams, and defeating each of the Gym Leaders in turn.