The game takes place in the Sinnoh region, where players assume the role of a young trainer with a Pokémon. The story begins with the player receiving a Pokémon from Professor Rowan, a renowned Pokémon researcher. The player's goal is to travel throughout the Sinnoh region, battling other trainers and their Pokémon to earn Badges. Along the way, the player must thwart the plans of the nefarious Team Galactic, who seek to exploit the power of the legendary Pokémon Dialga.