Humans occupy the lower decks of a space ark; mutants control the upper decks. But is there life beyond? Based on a story by Robert Heinlein, this episode of Dimension X originally aired on August 2, 1951.

Featuring "adventures in time and space told in future tense", Dimension X aired over NBC from April 8, 1950, through September 29, 1951. The series adapted stories by the modern masters of science fiction, including Ray Bradbury, Robert Heinlein, Clifford Simak, Theodore Sturgeon, and many others.