An estranged wife shows up after a nearly 7 years of disappearance -- thought to be dead, to prevent her husband from marrying his new love until someone kills her.

A Martian invader crashes his spaceship conveniently close to the workshop of a scientist who is developing an interplanetary craft. If the extraterrestrial Purple Monster can complete the rocket ship and return to Mars, he will be able to start a full-scale invasion of Earth. Good thing Craig Foster sets out to thwart the Monster's mission!

In order to win back his girlfriend, Mike Shayne promises to give up his detective practice and get a job as riveter in an aircraft plant. He quickly finds himself investigating the theft of industrial diamonds from the plant's safe and, utilizing a variety of false identities, traces them first to a dress factory and later to a Hawaii-bound ocean liner. Escaping several attempts on his life, he is able to uncover a Nazi smuggling ring, but the location of the missing diamonds continues to elude him.

A crime writer believes that a man imprisoned for committing the notorious "Flower Shop Murder" is innocent of the crime. He believes he knows who the actual culprit is, and sets out to befriend the man and get enough evidence to prove that he is the real killer.

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.

When police officer Moe Finkelstein and his colleague Officer Salomon are ordered to serve as bodyguards to German consul Karl Baumer by the mayor of New York City, Finkelstein turns in his badge, convinced he has to quit the service because the man is a Nazi.

The story of an egotistical crime writer who gets involved with the case of a notorious art thief (who is believed to be dead) while at the same time romancing a lovely young actress who's in a play that also happens to be the cover for massive jewel job. Art connoisseur and criminologist George Melville is hired to track down art thieves, assisted by perky Claire Peyton and goaded by Phil Bane, the roaring newspaper editor who has employed him. The mastermind poses as a theatrical impresario and stages a war drama, replete with loud explosions, to divert attention from his band of thieves, who are cracking safes in a bank adjacent to the theater.