After the events unfolded in Paper Mario, and with the Star Rod safely back in Heaven, all is peace. Bowser was defeated, and the Mushroom Kingdom was entering a glorious era of prosperity.

However, Kammy and Bowser sought revenge. They would not stand by and let the Mushroom Kingdom flourish as their evil plans had been crushed in front of their eyes.

As odd as chances were, one day, they came across an evil maniac scientist called Dr. Hasl, who had evil plans to conquer the peaceful Mushroom Kingdom as well. Bowser and the Doctor joined forces, and they used the power of technology to create a star-hungry monster – which they would use to crush the wishes of people and make them submit to their power.

Now Mario must stop them!