A boring day in the spaces lanes above Terra quickly turn to terror when Commander Corry's spacecraft is disabled after being struck by a meteorite and plummets out of control towards the artificial planet's spaceport.
Commander Corey, Cadet Happy and Carol Carlisle struggle to identify Thormanoids, alien humanoids that resembling Earthlings and are bent on galactic domination, who have infiltrated the ranks of the Space Patrol.
Deadly weapons are outlawed on Terra, but smugglers have adapted ordinary ray guns to fire explosive missiles. Commander Corry and his friends investigate the racket, but are captured and imprisoned in the hold of a refrigeration ship bound for the far reaches of the galaxy.
Commander Corry sends Tonga to investigate reports that a number of travelers have disappeared in the space lanes near Mercury. When Tonga fails to keep a rendezvous with Corry, Happy and Robbie, the men attempt to retrace her steps and are forced to land on a barren asteroid inhabited by a man who claims to know the secrets of eternal youth.
The Space Patrol take a ship back into the past to Earth in 1952 with an urgent delivery of blood needed at the time. The star drive fails during the flight and the team land in an unknown time period.
An aging prospector strikes it rich when he discovers a vein of rare metal on a remote planetoid. He plans to keep a small portion for his own needs and turn over the rest of the claim to the United Planets but his shiftless relatives have other ideas and try to force the old man to reveal the location of his mine. When Commander Corry and friends intervene, the miner's relatives get their revenge by blowing up the entrance to the valuable mine - with the Space Patrol members inside.