Road to Salina (1970)

Jonas, a young drifter, is wandering in a deserted area on the road to Salina, Mexico. He stops at a desolate roadside service station when Mara, the owner, identifies him as her son Rocky, who disappeared four years ago. Feeling sorry for Mara, he decides to stay on and meets Mara's friend Warren and Rocky's sister Billie, but dark facts are to be revealed about the disappearance of Rocky.