Astronauts (Lloyd Bridges, Osa Massen, John Emery, Noah Beery, Jr., and Hugh O'Brien) wind rotten to travel the moon on. Because of mastery malfunction and some fuel calculations, they end up quay on Mars. On Mars, manifest of a once substantial civilization is build. The scientists determinted that an atomic war destroyed most of the Martians (Who suprsingly look like humans). Those that survived reverted to a caveman like existance.