A small ship travels to a rotating space station. Aboard the station, a group of starfish-like beings discuss how to warn humans of an impending disaster, deciding on contacting Japanese scientist Dr. Kumara. Meanwhile, flying saucers are spotted over the skies of Tokyo, baffling scientists. A journalist tries to get a statement from Dr. Kumara about the sightings, but Kumara replies that there is not enough evidence to formulate a hypothesis. At an observatory, Professor Isobe spots an object in his telescope apparently releasing smaller objects.
Mankind has achieved space flight capability and built "The Wheel" space station in orbit 1,075 miles above Earth. It is commanded by its designer, Colonel Samuel T. Merritt (Walter Brooke). His son, Captain Barney (Eric Fleming), having been aboard for a year, wants to return to Earth.
A group of highly qualified single men, including Dr. Richard Stanton (William Lundigan) and Dr. Jerry Lockwood (Richard Carlson), are recruited for a top secret project. They undergo a series of rigorous physical and psychological tests, during which Stanton becomes attracted to the beautiful Dr. Jane Flynn (Martha Hyer), one of the scientists testing the candidates. After most of the candidates have been eliminated from consideration, the four remaining are told about the purpose of the project.
After a botched attempt at suicide, Nora King (Kathleen Crowley) revives and discovers that her building has no electricity or water. She soon realizes that Chicago is deserted when she wanders out into the empty, quiet streets. Stumbling over the body of a dead woman, she encounters Frank Brooks (Richard Denning), another person who has just recently revived after being beaten in a robbery.
Rocky Jones attempts to save the inhabitants of a planet about to collide with a moon. The empress of the planet, however, is suspicious. While Rocky and his crew finally succeed in evacuating the planet in time, Cleolanthe's pride and vanity are a major hindrance. Finally, however, as the last of the planet's population leaves, Cleolanthe arrogantly declares that she will stay behind. Her assistant, however, refuses to allow this, and literally picks her up and carries her on board Rocky's own ship. She watches in despair as the moon crashes into her planet, the two bodies destroying one another instantly. As the ship heads for the new home that has been chosen for her people, Cleolanthe finally realizes that she had been wrong, and that, as one of her underlings has stated, it is the people that make a nation, not the land itself. She finally reconciles with Rocky and his crew, and sincerely thanks them for their efforts in her behalf and that of her people. This marks the end of the character Cleolanthe in the Rocky Jones series. Succeeding episodes contain a new villain.
Nyah, a female alien commander from Mars, dressed in shiny black vinyl, heads for London in her flying saucer. She is part of the advanced alien team that is looking for Earth men to replace the dying male population on her world. Because of damage to her saucer, caused by entering Earth's atmosphere and then colliding with an aircraft, she is forced to land her damaged flying saucer in the remote Scottish moors, near a local village. She is armed with a raygun that can paralyze or kill, and she also has a tall, menacing robot named Chani.
In early 1950s southern California, Dr. Clayton Forrester (Gene Barry), a scientist who had worked on the Manhattan Project, is fishing with colleagues when a large object crashes near the town of Linda Rosa. At the impact site, he meets Sylvia Van Buren (Ann Robinson) and her uncle, Pastor Matthew Collins (Lewis Martin). Van Buren was told that the meteorite came down at a low angle, while Forrester observes it appears far lighter than normal for its massive size. His Geiger counter also detects it is slightly radioactive, but the object is still too hot to examine closely. Unable to account for these anomalies, Forrester is intrigued and decides to wait in town overnight for the object to cool down.
Set in a future 1970, the United States is considering building bases on the Moon. Colonel Briteis (Donna Martell), Major Bill Moore (Ross Ford), and Doctor Wernher (Larry Johns) are sent to orbit the Moon to survey landing sites for future lunar missions. However, Dr. Wernher is an impostor whose mission is to destroy the US's Earth-orbiting space station, which he plans to do by colliding the rocket with the station on the way back from the Moon.
An expedition to the moon encounters a race of "Cat-Women", the last eight survivors of a 2-million-year-old civilization, deep within a cave where they have managed to maintain the remnants of a breathable atmosphere that once covered the Moon. The remaining air will soon be gone, and they must escape if they are to survive. They plan to steal the expedition's spaceship and migrate to Earth.
Orville (Lou Costello) is the oldest orphan at the Hideaway Orphans Home. He accidentally winds up inside a truck heading to a top-secret laboratory, where he is placed under the guidance of lab worker Lester (Bud Abbott) to help load supplies onto a rocket ship. While on board with Lester, Orville hits the ignition button and the rocket blasts off, flying across the country to New Orleans, where Mardi Gras is in progress. They exit the ship and witness "hideous creatures", which are actually costumed celebrants, and conclude that they have landed on Mars.
Late one night, young David MacLean (Jimmy Hunt) is awakened by a loud thunderstorm. From his bedroom window, he sees a large flying saucer descend and disappear into the sandpit area behind his home. After rushing to tell his parents, his scientist father (Leif Erickson) goes to investigate David's claim. When his father returns much later in the morning, David notices an unusual red puncture along the hairline on the back of his father's neck; his father is now behaving in a cold and hostile manner. David soon begins to realize something is very wrong: one-by-one he notices certain townsfolk are acting in exactly the same way. Through his telescope, David sees child neighbor Kathy Wilson walking in the sandpit, when she suddenly disappears underground. David flees to the police station for help, and he is eventually placed under the protection of health-department physician Dr. Pat Blake (Helena Carter), who slowly begins to believe his crazy story.
The plot dealt with the first manned spaceflight (piloted co-ed by Duff and Bartok) against the backdrop of Duff's character's failing marriage, his wife's infidelity and murder (of which Duff is suspected), and his budding romance with Bartok, who plays a renowned mathematician working on the space project.
Commando Cody (George Wallace) is a civilian researcher and inventor with a number of employees. He uses a streamlined helmet and a sonic-powered rocket backpack attached to a leather flying jacket. Cody also uses a rocket ship capable of reaching the Moon. When the U. S. finds itself under attack from a mysterious force that can wipe out entire military bases and industrial complexes, Cody surmises (correctly) that the Earth is coming under attack from our own Moon. He then flies his rocket ship there and confronts the Moon's dictator, Retik (Roy Barcroft), who boldly announces his plans to both conquer Earth and then move the Moon's entire population here using spaceships.
An American astronomer obtains images of Mars suggesting large-scale environmental changes are occurring at a pace that can only be accomplished by intelligent beings with advanced technology. At the same time a colleague claims to have been contacting Mars by radio, using technology stolen from the Nazis after World War II. He communicates first through an exchange of mathematical concepts, like the value of pi, and then through answers to specific questions about Martian life. The transmissions claim that Mars is a utopia fueled by nuclear power, which has led to great technological advancement and the elimination of scarcity, but that there is no fear of nuclear war.