Title and credits roll over the evening launch of a missile and star field. We open with a police car driving into frame. It is early evening on a desolate highway in the desert. Sheriff Cramer (Lee Roberts) is searching for two inmates who've escaped. He will next search the Dayton rocket installation. Steve Dayton (Richard Travis), Dirk Green (Michael Whalen) and Col. Wickers (Henry Hunter) are reviewing Dirk's advanced designs in rocket science. Wickers heaps praise on Dirk, but tells him the government will be taking over, explaining, "Gentlemen, you must understand that missile experimentation is government business. Strictly government!" Steve tries to champion private enterprise, speaking more for Dirk than himself, which he confides later to Col. Wickers. Wickers tells the pair, "I'm only carrying out orders. Tomorrow morning, a team of government experts will take over." The meeting is interrupted by the Sheriff. He tells of the escape of two prisoners from the County Farm and asks permission to search the grounds and around the rocket. The rocket itself is protected by an electric perimeter fence. Dirk escorts the Sheriff out of the office. Steve and the Colonel discuss how he came to collaborate with Dirk. He reveals the project's scope includes a trip to the moon. June Saxton (Cathy Downs) enters the office and is introduced as Steve's fiancée. Dirk and the Sheriff arrive at the rocket site gate. Dirk warns the Sheriff not to touch the fence. As he gets his key to unlock the switch box, he notices the lock is unsecured and the power already cut. While the pair search around the rocket, the two escaped prisoners wander around inside the rocket. Gene Fennell (Tommy Cook), the shorter, tougher of the pair complains about the choice of hide out, "This was a great idea, like hiding out in a gas chamber. The place gives me the creeps." [Note: While credited as Gene, his character is frequently addressed as Gary.] Lon (Gary Clarke) is tall, slim and the smarter of the two. They decide the rocket may not be the best choice after all, but when they try to leave they notice Dirk and the Sheriff below. The convicts walk up the ladder to the control room. The Sheriff insists the rocket be searched, but Dirk convinces him he should search his own rocket. Dirk opens the hatch to the control room, sees the pair, smiles and tells the Sheriff, "There's no one here!" Dirk walks back down the latter, closing and locking the hatch behind him. Gene and Lon are locked in and very unhappy about it.Dirk returns to the office. Steve and June are having a drink and invite Dirk to join in the celebration. Dirk is not in the mood and tells them, "Nobody's going to take over my work. I designed and built that ship to fly into space and I'm going to see that it does." Dirk grabs a gun from his desk and exits the office. The escapees argue, with Lon expressing regrets for his involvement with Gene. Dirk enters the rocket with food for his newly acquired "crew". He presents Lon and Gene with a fait accompli. They can join Dirk as his crew to fly the rocket to the moon or be shot and killed on the spot. Gene still wants to leave, but is persuaded when Dirk completes his proposal with a gun in his hand. Lon is intrigued by the idea and agrees. The pair change clothes and prepare for launch. In the office, the rocket launch system activates which gets Steve and June's attention. They go to the rocket to investigate. Dirk prepares for launch and instructs Lon and Gene on their duties. Steve and June enter the ship. Before they can leave, the door closes trapping them inside a compartment with no climate control. They don oxygen masks and prepare themselves for launch.Launch was successful, but a counterbalance indicator alarm indicates something wrong below deck. Lon checks and discovers the two stowaways. Steve requires assistance to be brought around. Dirk proudly announces, "We're thousands of miles in space. Everything is working as we designed it. We're on course and everything is under control." Steve and June are introduced to Dirk's crew. Dirk laughs when he tells them they are the two escaped convicts. Gene immediately takes a liking to June and a dislike for Steve. Steve, Dirk and June check mission parameters. Steve and Lon go topside to check on equipment, and Dirk goes below. That leaves June and Gene alone. Gene makes a clumsy and unwanted pass at June. She tries to fight him off. Dirk's early return results in a warning to Gene to leave June alone, and a fight between the two takes place. A meteor shower stops the fight. A battery strap is broken, and Dirk goes to secure it. The battery falls on his head and he is seriously injured. While Gene and Lon move the battery, Steve attends to Dirk. Realizing he is dying, Dirk tells him, "The controls are preset so the ship will land in a specified area. Don't change it, you must land there." He gives Steve a medallion and tells him not to lose it, he will need it where they are going. Before he dies of his injuries, Dirk calls out, "Lido. My Lido. Forgive me. Forgive." Steve examines the medallion and reviews their situation. He suspects something unusual will happen on the moon. They approach the moon, and the automatic sequence for landing begins. They land and change into their spacesuits. They descend to the moon's surface and begin their exploration of the satellite. They stay in shadow to avoid the heat of the direct sun. They pass an outcropping rocks. The pile begins to move. They hear something, but dismiss it as a rock slide. The rock creatures begin to follow them. The four walk through a valley, past another rock creature, but this time they see it move. June screams and they see three more creatures all coming from different directions. They try firing pistols at the rock creatures, but bullets have no effect. They run to a cave to hide. Once inside, they notice the creatures won't enter the cave. They walk back deeper into the cave system. Lon discovers a torch, and June sees a light deeper inside. They discover a lighted torch, which means there is oxygen in the cave. They remove their space suits, secure them behind some rocks, and explore further. They conclude a higher form of life lives in the caves. Gene threatens to return to the ship, but wanders deeper into the cave. He encounters something, then screams. They smell gas as a hooded figure confronts them. They collapse.Sometime later they wake in the well-appointed throne room. The Lido (K.T. Stevens) enters wearing an elaborate gown and headdress. She is blind and welcomes them to Olanda. She introduces herself and sits on her throne. She offers the visitors/captives food and drink, provided by her court of eight beautiful women. The four eat the food provided and proclaim it delicious. The Lido proudly tells them, "I am pleased to see that you find of offerings satisfying. It may interest you to know that the food in front of you was produced long before I was born." The astronauts wince, then all put the food back down on the plates. A wine bearer notices Dirk's medallion around Steve's neck and reports it to the Lido. The Lido asks for the medallion and Steve is escorted back to the throne. Alpha (Nina Bara) takes the medallion from around Steve's neck and presents it to the Lido. The Lido is happy thinking that Dark has returned from his mission to Earth. Steve is mistaken for Dirk, an error he is not anxious to correct until he can learn more of their circumstances. The Lido and Steve retire to another room to talk. She inquires about Earth and volunteers that their world is dying, "Our oxygen is disappearing. Our food supply is dwindling. Soon this satellite will be barren; devoid of life." The Lido also mentions that he is to be married to Alpha after his briefing is completed.Gene is now happy to be surrounded by beautiful women waiting on him hand and foot. He takes an immediate interest in Lambda (Laurie Mitchell) and they leave to be alone. Gene notices Lambda's diamonds and asks for the source. In the throne room, Lon takes a shine to Zema (Leslie Parris as Marjorie Hellen). June starts to display a little insecurity and jealousy. The Lido tells Steve, still thinking he is Dirk, "From what you tell me Dirk, the planet Earth would not satisfy our needs. Fortunately I have another destination in mind. Tell the Earth people they are not to consider themselves prisoners. They may move about as the wish, provided they do not try to escape. You will rejoin them now." Steve and June talk. He reveals the Lido is blind and thinks he's Dirk and they want the rocket. Lon and Zema get acquainted. She tells him of her world and the rock creatures aversion to oxygen. When Steve tells June of his upcoming wedding to Alpha she reacts badly. She gets in a fight with Alpha and reveals Steve's real identity. Lon and Steve breakup the catfight. Alpha proclaims, "She will die," then storms off. They plan their escape as Alpha reveals the plot to the Lido. The Lido pretends she knew Steve's real identity, but Alpha does not believe the story. She challenges her leadership, using some mind control technique, but is unsuccessful. The defeated Alpha pretends to follow her Lido's orders. Deep in the caves Gene is gathering up a couple of huge, uncut diamonds. Alpha takes it upon herself to unleash a giant spider to track down and kill the earth people.Steve, June and Lon wander the caves looking for Gene and their spacesuits. They find the spot where they hid them, but discover them now missing. Gene and Lambda join the three. Lambda warns them they must leave the caves immediately, but concludes that it is now too late. She runs off and is caught and killed by the giant spider. The four are captured and returned to the throne room. Steve chats with Alpha. She reveals to Steve that she still intends to proceed with the wedding. Alpha hypnotizes Steve to obey her orders. Alpha and the Lido talk, but the discussion ends with a knife plunged into the Lido's back. Alpha succeeds in taking over as the new Lido. Alpha's first order of business is June's execution followed by her wedding to Steve. Steve, dressed in a ceremonial gown, pronounces June's death order. June is hauled off to the extermination chamber. The ceremonial dance begins, as June is chained to a cross and a giant spider is released from a caged section of the cave. Zema has fallen in love with Lon, and helps in his escape with Gene. She gives the pair a key to the closet containing their space suits and tells them where to find June. She promises to set Steve free to join them in their escape. June screams when she sees the spider approaching and faints. Gene and Lon shoot the giant arachnid, a white powder is expelled from its mouth as it collapses in death. They unchain June. Gene dismisses himself to retrieve as many diamonds as he can carry. Alpha notices the missing earthmen and halts the ceremony. Lambda confronts Alpha, using her mind control talents, releases Steve from his spell. She and Alpha have a mind control battle. Weakened by her earlier battle she decides to sacrifice herself for Lon's safety and throws a bomb in the throne room, which causes the oxygen to be evacuated. Steve, Lon, and June don their space suits and exit the cave. As Alpha is dying she still tries to influence Steve with her mind control. It almost succeeds, but she dies first. Gene, carrying two large bags of diamonds, hurries to join his shipmates. The three start back for the ship, staying in the shade. Gene exits the cave, but a rock creature is between him and his shipmates. Gene's greed overcomes his better judgment, and he refuses to drop the diamonds which is hindering his progress. He is surrounded by rock creatures and wanders back into the sun. His body begins to smoke. He screams, then he bursts into flames. All that quickly remains is a smoldering skeleton. The three survivors get back to the ship. We close with the rocket blasting off from the moons surface.