A gunfighter, stranded in the desert, comes across the aftermath of a stage robbery, in which all the passengers were killed. He takes one of the horses to ride to town to report the massacre, but finds himself accused of it. He also finds himself accused of the murder of the local banker, and winds up hiding in the basement of a house where the local sheriff, who is very sick, lives with his daughter.

An evil alien brain, bent on world domination, takes over the body of an atomic scientist, while a "good" alien brain inhabits the body of the scientist's dog and waits for an opportunity to defeat the evil brain.

A fungus dubbed "Blood Rust" from outer space threatens to destroy the Earth.