Commander John J. Adams (Leslie Nielsen) and his crew are on a rescue mission to a failed colony planet, but when they get there they are told by the only survivor of the mission that they must turn back and not land on the planet. When they land anyway, the survivor tells them that he cannot be held responsible for anything that happens to the crew. Upon landing, the crew is greeted by Robby the Robot, who leads them to the extremely technologically advanced home of Dr. Edward Morbius (Walter Pidgeon) and his daughter Altaira (Anne Francis). The planet seems idyllic until an invisible monster begins attacking the ship and its crew. The crew believe that Morbius has the power to stop the monster, but he is suddenly uncooperative.