In 2257, the crew of United Planets Cruiser C-57D, led by Cmdr JJ Adams (Leslie Nielson), Lt Farman (Jack Kelly) and Dr Ostrow (Warren Stevens),come to check on Altair-4's first settlers. All have been killed, except the mysterious Dr. Morbius (Walter Pigeon) and daughter, Altaira (Anne Francis),
by an invisible being, per Dr Morbius. Adams is skeptical of Morbius' story, his palacial setting, Earth-type animals seen, & Robby the Robot, who first greeted the crew. Adams states he'll have to return Morbius to Earth, but Morbius suddenly gives Adams, Farman & Ostrow an underground tour of still-operating technology, left by the Krell, inhabitants who disappeared 2000 centuries ago. Morbius explains that many devices are controlled by the mind & that even his has expanded. Adams & Altaira realize they have an attraction, which Morbius is aware. In a night attack on the ship, an invisible creature wipes out half the crew including Farman. Adams & Ostrow confront Morbius, who is unaccepting of Adams' theory that Krell technology is providing the invisible attacker, conjured up by Morbius' innermost mind - the id -to drive away Adams & his crew. Robby alerts that ' something ' is coming, & the group escapes into the underground Krell maze as Morbius' house is torn apart by something invisible.