The Hanging Tree(1959)

From The Prize Novel -- A Picture Of Thundering Power!

Joseph "Doc" Frail is a doctor with a past he's trying to outrun. While in Montana, he comes across a mining camp with a hanging tree and rescues a man named Rune from the noose. With Rune as his servant, Frail decides to settle down, and he takes over as town doctor. He meets Elizabeth, who is suffering from shock, and the two soon fall in love. But when Elizabeth is attacked, Frail's attempt to help her lands them both in trouble.