Fawful tricks Bowser into eating a magic mushroom. The mushroom causes Bowser to begin inhaling everything around him, including Mario, Luigi and Princess Peach! Do the Mario Bros. have the guts to rescue Peach and escape? Players are in control of two separate storylines. One features Bowser and his efforts to stop an arch-villain from taking over his castle. Meanwhile, inside Bowser, the microbe-sized Mario & Luigi must muscle their way through challenges and keep their nerve if they want to find a way out. They take action to control Bowser from the inside â€" but without his knowledge.
