Monako must go up against his old enemy, Muro, who is attempting to gain control of the Pacific and west coastal areas of the Americas, specifically the Panama Canal.; A daring bank robbery leads the Purple Mask after the gang responsible and he discovers that the bank's President is involved with the crime.; Carter rescues an Earth girl, Brenda Hale, who is agent of the Space Army, Women's Division, 4th Regiment and whose ship has been grounded by the Martians, and he learns that Mars intends on invading the Earth to make it one of her colonies.; Marvex looks into the troubling case of a man sitting on death row awaiting execution for a crime in which witnesses in his favor disappeared mysteriously before the trial.; Foreign agents attempt to steal the secret super-charged engine invented by test pilot Don Gorman, an invention allowing airplanes to achieve speeds over 1000 mph!; Breeze has made good his escape from Miracle City with Ann and enter into the civilized world, where they are informed by Frenchy that civilization as they knew it had been destroyed by the War of 1945.; Edith's brother, a member of the Nazi forces, convinces Edith to keep Trojak out of their invasion attempts, not knowing it's all a plan to capture Trojak.; K-4 and his assistants are assigned the job of tracking down an enemy zeppelin that is being used to drop mines by parachute over vital installations.