In a small African port, a tawdry bar is run by a old man named Webb Fallon. Fallon is actually a vampire, but he is becoming weary of his "life" of the past few hundred years.

An escaped criminal impersonates a Police Commissioner, causing no end of trouble to a determined Federal Agent.

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.

Commando Cody, 'Sky Marshal of the Universe', works with American scientists Joan Gilbert and Ted Richards in the development of a flying suit and a rocket to the Moon. When the nation's defences are being sabotaged and destroyed, Cody learns that an atomic-gun is being used and that the men on the moon are the culprits.

Monte Walsh is an aging cowboy facing the ending days of the Wild West era. As barbed wire and railways steadily eliminate the need for the cowboy, Monte and his friends are left with fewer and fewer options. New work opportunities are available to them, but the freedom of the open prarie is what they long for. Eventually, they all must say goodbye to the lives they knew, and try to make a new start.