The story begins with the space capsule of an American astronaut named Captain Frank Chapman (played by Dean Fredericks) experiencing mechanical difficulties while in orbit around Earth. In an attempt to repair the capsule, Chapman is forced to exit the spacecraft and make a spacewalk. However, he gets too far away from the capsule and becomes untethered, floating away into the void of space.
Chapman eventually lands on an asteroid-sized planetoid and discovers that it has a breathable atmosphere, though it has significantly lower gravity than Earth. He encounters the planetoid's humanoid inhabitants, who are diminutive in size and wear metallic suits. These people have their own society and civilization, and they explain to Chapman that they are unable to help him return to Earth.
As Chapman settles into life on the planetoid, he learns that the planetoid is in danger of being drawn into the gravity well of a larger asteroid. If this happens, it could result in the destruction of the planetoid and its inhabitants. Chapman becomes involved in the planetoid's efforts to counter this threat and save their world.
During his time on the planetoid, Chapman also becomes romantically involved with Liara (played by Coleen Gray), one of the inhabitants. As the two work together to try to save the planetoid, they face various challenges, including the presence of hostile alien beings who are determined to undermine their efforts (1961).
Director: William Marshall
Stars: Dean Fredericks, Coleen Gray, Anthony Dexter