A feud between two cadets causes the wreck of the Commanders flagship during interplanetary war games. Tom, Astro, and Manning suddenly find themselves the target of deadly atomic torpedoes while taking part in maneuvers to repel a mock invasion from space. Cadets Manning and Eric Rattison (Sutton) tension builds when Eric is temporarily assigned as an extra member of the Polaris Crew. Past differences are insignificant when the two are trapped together fighting for survival and facing death.