While a distinguished astronomer is giving a lecture in a planetarium, a shot rings out and one of the audience members is found dead. A tough detective and a brassy female reporter lock horns as they both try to break the case.

A Professor has an invention that will bring down planes causing them to crash and Dawson is forcing him to use it on those carrying money. When Tim arrives to investigate he is mistaken for a noted outlaw. So he assumes that identity to force Dawson to make him a partner. But just as a plane bringing Tim help is arriving, his true identity is revealed and while he is a prisoner, Dawson forces the Professor to start his machine.

Krag Sabine has aroused the wrath of all the ranchers by stealing their land with the aid of his henchmen, led by Ace Barco; when Lafe Martin objects, the outlaws shoot him down. Lucky Randall promises Ann Martin he will avenge her wounded father. He sets up headquarters on the Martin ranch and sends for Bob Merritt and his men, the Texas Playboys (Jesse Ashlock, Leon McAuliffe, Cotton Thompson, Junior Barnard and Luke Wills). Krag organizes his remaining men for an attack on the ranch. Lucky's men get the upper hand but Krag escapes with Ann as his hostage.

A pair of nightclub owners run a string of escort bureaus where men pay for the "companionship" of young women. The district attorney sends an undercover agent to infiltrate the bureaus.

When newspaper reporter Tim Collins, of the "Post", is slugged while investigating the shooting of a big-time gambler, he sets out to get his man with such determination that he ends up in jail. There, he discovers a "parole racket" which involves a crooked politician, and he faces death to get the story for his paper.

A grifter in a boxing scam learns a better way from an orphan and a beautiful girl.

Feature version of the 1938 film serial FLASH GORDON'S TRIP TO MARS. Flash Gordon fights Ming the Merciless once again to ensure the survival of the Earth.

Police Inspector Steve Trent is called to the Radford Arms, a high-rise apartment building that has been taken over by a bank and its apartments now-unoccupied.

Silent Madden and his daughter Molly have left the criminal underworld of San Francisco thanks to the wise teachings of Chang Low, a Confucian master. But the evil Black Mike Sylva is determined to frame Madden to avenge a mistake from the past…

Two vaudeville performers adopt the son of an actor friend.

A mad scientist uses captured criminals as experiments for his study on "the criminal mind" aboard his private ship.