All aboard for an island RPG adventure starring Mario and Luigi! The brothers set sail for Shipshape Island (part ship, part island) to navigate the vast world of Concordia. Play as a bearded couple and explore islands that range from tropical rainforests to bustling cities. Along the way, meet new friends to help you on your journey and meet familiar faces from the Mushroom Kingdom like Peach and Bowser. Keep the "brotherhood" afloat and rely on Mario and Luigi's connection to save the day by employing the brothers' moves to overcome obstacles and the brothers' powerful attacks to claim victory in a dynamic turn-based battle.