He-Man and Man-At-Arms discover a crashed spaceship piloted by a robot. They take him back to the palace, where Man-At-Arms manages to repair the robot, who tells them his name is Roboto and he is a space explorer from the planet Robotica. He expresses his interest to explore Eternia, but during the night he is captured by Modulok, Man-At-Arms' sworn enemy! Modulok reprogrammes him to do his own dirty work, which involves the dastardly experiment of transplanting Man-At-Arms' brain into Modulok's extra head.....