Mars Mason was an intergalactic postal worker of the Inter Planet Mail System who encountered many villains and alien monsters on his deliveries. These included the villainous Killraye of Jupiter, the tough-tails, the spear men, and the sour snouts. He also meet the Air Queen on one of his adventures. Mars had no powers, but he was a good fighter, willing to endure torture and death to protect American secrets. He sometimes carried a ray gun and he traveled throughout the solar system in his own ship.