The residents of a small town are excited when a flaming meteor lands in the hills, until they discover it is the first of many transport devices from Mars bringing an army of invaders invincible to any man-made weapon, even the atomic bomb.

Cleve Marshall, an assistant district attorney, falls for Thelma Jordon, a mysterious woman with a troubled past. When Thelma becomes a suspect in her aunt's murder, Cleve tries to clear her name.

A prim psychology professor fights to hide a murder she committed in self-defense.