A couple discovers that their friend has gone missing. Their investigation leads them to believe that anti-semites are behind the disappearance.

A convict is forced to participate in a prison break even though he only has a year left on his sentence.

A mysterious plague, the Purple Death, ravages the earth. Dr. Zarkov, investigating in his spaceship, finds a ship from planet Mongo seeding the atmosphere with dust. Sure enough, Ming the Merciless is up to his old tricks. So it's back to Mongo for Flash, Dale, and Zarkov.

In 1915 France, Major Brand commands the 39th Squadron of the Royal Flying Corps. The young airmen go up in bullet-riddled "crates" and the casualty rate is appalling, but Brand can't make the "brass hats" at headquarters see reason. Insubordinate air ace Captain Courtney is another thorn in Brand's side...but finds the smile wiped from his face when he rises to command the squadron himself. Everyone keeps a stiff upper lip.