The Cheyenne Social Club (1970)

Cowboy John O'Hanlan (James Stewart) is surprised to learn that someone's left him a business in Cheyenne, Wyo. He sets out to claim it -- and is shocked to discover that it's a brothel. Madam Jenny (Shirley Jones), who runs the place, is dismayed when O'Hanlan wants to close it down, but his plans are derailed when he finds out that a local customer has beaten Jenny. He kills the man in a shootout, and then must protect himself and the girls from the dead man's vengeful clan.