Trackdown (1976)

When his sister Betsy packs up and leaves the familys Montana cattle ranch to find fame and fortune in Hollywood her brother Jim decides to follow after her to make sure she doesnt get into trouble Hes a little too late however since almost as soon as she gets off the bus Betsy has her belongings stolen then gets kidnapped gangraped and is sold to a pimp to work for him as a prostitute It is now up to Jim with help from social worker Lynn to rescue his sister and set things right