A mechanical monster from outer space has been kidnapping the little boys of Mouseville and is sending them to his hideout on an unknown planet. The town's police chief calls Mighty Mouse onto the case. Finding a space helmet outside a house, our hero puts on the device and is taken to the planet, where he destroys the metal monster. Mighty learns that the Monster is the creation of a kindly old man who was the victim of an ancient curse of an old witch.