Kim Spalding

The first manned expedition to Mars is decimated by an unknown life form.

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. (imdb)

A doctor tests his theory that blood diseases can be cured by atomic radiation by using prison inmates as experiments. (imdb)