Kurt Russell

During a shootout in a saloon, Sheriff Hunt injures a suspicious stranger. The doctor's assistant, wife of the local foreman, tends to him in prison. That night, the town is attacked and they both disappear—only the arrow of a cannibal tribe is found. Hunt and a few of his men go in search of the prisoner and the foreman's wife.

A research team in Antarctica is hunted by a shape-shifting alien that assumes the appearance of its victims.