Natalie Ravenna (Shirley Knight) sets off on a drive in a family station wagon. She gives a ride to a strapping young man, Killer (James Caan), who had been a college football star but had sustained a serious head injury and was given one thousand dollars to go away.
On their first night together, in Natalie’s motel room, she orders Killer around and makes him show her his muscular body. She tells him she is pregnant and had given him the ride to have a one-night affair with him, but then she sends him to his own room.
Natalie drives Killer to the home of a one-time girlfriend of his whose father had once promised him a job, but that family wants nothing to do with him and Natalie takes him with her when she drives away. While they travel west she twice comes close to finding him work and a place to stay, only to decide that Killer would be taken advantage of. She also twice leaves him at the side of the road, only to change her mind.
At their next stop Natalie makes a collect phone call and it is revealed that she left a husband at home when she took off. During a subsequent call days later her husband pleads with her to return home, saying he will do anything to make her happy.
Things become complicated when Natalie gets involved with a handsome but lonely highway patrolman, Gordon (Robert Duvall), and after a night out he takes her back to his place.