R.B. Ruger is an escaped convict and migrant worker traveling with another migrant worker, his friend Buddy, who is like an older brother. Buddy is a union organizer, and his reputation as a "Communist" has gotten the two in trouble wherever they've been.

They find a job in Sheridan, Wyoming, on a ranch owned by a Western movie star named Mr. Wakefield, working under the supervision of a man named Tyler, who, when he hires them, uses the knowledge of them being union organizers with negative reputations as "Communists" as a bargaining chip.

In town, R.B. flirts with a light-skinned Black girl named Bernadine at the bar. Mr. Wakefield offers to lend R.B. his car to take her back to the ranch. R.B. drives around with the girl. They eat at a restaurant, where R.B. threatens some men who throw racist slurs and remarks their way. Then, they find an abandoned shack where they lie down.

They're interrupted by men who drive up outside. The men have Buddy, who is beat up, in their car. They arrest R.B., presumably for auto theft, even though Mr. Wakefield is on the road in his Cadillac. R.B. realizes Mr. Wakefield set him up.

R.B. and Buddy are held captive without knowing what will happen to them. R.B. learns that Mr. Wakefield is raping Bernardine in his car and has wanted R.B. to take her to the ranch for that reason.

The two are eventually released, which clearly indicates they should leave town to stay alive and free.

They find a cherry-picking job in Montana. Buddy sends for Bernadine, who joins them. Buddy tells R.B. that Mr. Wakefield is shooting a movie nearby. One day, they see him in their town, and Buddy asks for a signature. He either doesn't recognize them or pretends not to. R.B. is jealous because he thinks Bernadine is more interested in Buddy than him. Buddy tells stories about ancient highways under the water, and Bernadine pays rapt attention.

The feds come and interrogate Buddy about his reputation as a Communist. Buddy shows them a business card of Mr. Wakefield's, on which he has forged the signature, and a note saying, "Call me if the feds ever come around." Buddy uses Mr. Wakefield as a fake friend in high places to deter the feds. After this encounter, R.B. confesses his past--how, as a child, he killed a child who bullied him, and it has haunted him since--to Bernadine. She tries to reassure him of his good moral character.

R.B. can tell Buddy isn't done with Mr. Wakefield--he wants revenge. One day, they drive past Mr. Wakefield's cast and crew, out filming. Buddy hops out to give them a speech and wave around union pamphlets, even though R.B. thinks they won't make it out alive. A chaotic brawl ensues. R.B. and Bernadine run away, and then Buddy pulls up behind them in Mr. Wakefield's car, which he has stolen. They speed away with people in hot pursuit but find some of the crew blocked off the road. Buddy tells R.B. and Bernadine to get out and double back through the woods on foot. Buddy drives the car into the lake, distracting their pursuers. R.B. and Bernadine escape to Canada. R.B. says that while everyone says Buddy drowns, he swears he saw him drive through the lake on one of those ancient highways he was going on about and come out the other side.