King Bowser, a nasty dragon-like creature, wants to marry the pretty Princess Toadstool of the Mushroom Kingdom, a fantasy world where such things like Kinopi (Mushroom) people live. Bowser then threatens the Princess into marriage with him by turning the residents of the Mushroom Kingdom into stone. As the Princess heads to get her revenge on the tyrant, the Mario brothers, two plumbers who've somehow winded up in the Mushroom Kingdom, venture out to stop Princess Toadstool before she creates even more trouble, all the while defeating Bowser in the process.