Dr. Richard Stanton (William Lundigan) and Dr. Jerry Lockwood (Richard Carlson) are two daring young scientists who put their lives on the line to explore the universe. Seeking to discover a metal better suited to space travel, these pioneers launch into outer space to retrieve a meteorite. But, after fellow astronaut Walter Gordon (Robert Karnes) is violently killed when attempting to wrangle an enormous meteor, Lockwood panics, leaving Stanton to complete the mission on his own.

Scientists (John Agar, Hugh Beaumont) find a lost underground city of pale people and mutant slaves.

A scientist allows his young son to repair a robot, which comes under the control of an alien force.

In the 21st century, aliens invade the solar system. Using Mars as their base, they steal all of Earth's space stations then brainwash or kill the crews.

The outlaw Llano Kid (Gary Cooper) poses as a rich Mexican widow's (Emma Dunn) son and falls in love with a cousin (Fay Wray).

Mad scientist Dr. Roger Girard (Bruce Dern) is experimenting with transplanting second heads onto farm animals. When an out-of-control maniac, Cass (Albert Cole), stumbles upon Girard's place, he kills the landlord, injures his dim-witted son, Danny (John Bloom), and seriously hurts himself, as well. Seizing the opportunity, Girard grafts Cass's head onto Danny's body in an effort to save them both. The experiment is successful, but the creation goes mad and wreaks havoc on the countryside.

When his cattle begin to mysteriously disappear, rancher Jimmy Ryan looks for answers. He is soon horrified to learn that a giant dinosaur hiding in Hollow Mountain is eating his livestock.

Bud and Lou find themselves hurtling through space with an escaped gangster, eventually landing on a strange planet.

Three stooges, Moe, Larry, and Curly, accidentally land on Venus, where a series of adventures await them.