A spin-off from the hugely popular Dragon Quest series of role-playing games, Dragon Quest Monsters: Joker is similar to the Pokémon or Digimon style of creature-breeding battle games. The game takes place in Green Bays, a series of islands that teem not with ravenous, cheesehead-wearing Packer fans, but with more than 200 classic Dragon Quest monsters. Green Bays is home to the famous monster scout challenge, in which competitors scout monsters, synthesize new beasts, and pit them against one another in head-to-head battles.

Players take on the role of a boy who is sent by his father, Warden Trump, to infiltrate the monster scout challenge. The overall goal is to develop the strongest group of monsters by capturing, training, and synthesizing as many beasts as possible. Multiplayer modes let gamers battle and trade creatures via a local wireless connection, or players can use the DSs Wi-Fi capabilities to participate in both continental and global tournaments in the Wildcard World Cup.