Commander Adams (Leslie Nielsen) and his crew set out to investigate the disappearance of a colony of scientists on the planet Altair-4. After landing, they discover only two survivors, Dr. Edward Morbius (Walter Pidgeon) and his beautiful daughter Altaira (Anne Francis). They live a surprisingly prosperous lifestyle, attended to by Robby the Robot, a super-butler who speaks 188 languages and performs many amazing feats. But among Altair-4's many wonders, none is greater or more deadly than the human mind.