Princess Peach's voice has been stolen by Cackletta and replaced with explosives! Mario and Luigi with the help of Bowser follow her trail to the neighboring Beanbean Kingdom, where they interact with a new cast of characters in their quest to stop her.

Battle gameplay further continues the Super Mario RPG and Paper Mario traditions. Rather than merely making selections from a menu as in many RPGs, timing your button presses correctly can inflict or defend from extra damage.