Buzz Corry, the Commander of the Space Patrol is in route from the planet Terra to Earth. He is accompanied by Cadet Happy, a new Cadet and winner of the Corry Scholarship. They spot what appears to be a derelict guided missile. As they move to destroy the derelict, its engines fire and the missile launches toward the commander's craft. The missile narrowly misses and changes course to intercept. In reality, the missile is a disguised ""cosmic"" bomb controlled by Major Gorla from his fortress on Kars. The Major is assisted by Matra, an assistant to Terra' Secretary General. Together they plan to conquer the United Planets beginning with the murder of Commander Corry.