Nintendo Life writes: "Mario and Luigi have been to some pretty bizarre places, but none as weird as where they end up in Mario and Luigi RPG 3. You see, a mysterious epidemic is raging through the Mushroom Kingdom, causing people to inflate many times their normal size. The residents of the kingdom decided to unite in order to confront the disease, only to have their party crashed by a massive Bowser, who's under the control by a mysterious villain, Gerakowitz. Out of nowhere, Bowser sucks everyone up into his mighty belly."
