A man, Joe, flees across the moors at dusk. Inside a nearby cottage, a young woman, Sally, is putting her child to bed, while in the local prison a guard discovers Joe's escape. Sally hears the prison alarm bell ringing in the distance; she goes downstairs and is confronted by Joe, who has broken into the house. She knows him and shouts his name in fright.

Some time earlier. Joe is working as a barber's assistant alongside Sally, a manicurist, and is clearly jealous when she talks to male customers. She rejects his offer to take her to the 'talkies' and he throws the tickets on the floor in anger, ignoring the attentions of another female colleague: Joe is in love with Sally. When no one is looking another barber picks up the tickets, and later offers them to Joe's spurned admirer.

A local farmer, Harry, comes into the barbershop. Joe watches his obvious attraction to Sally with annoyance. Sally later changes her mind about going to the cinema with Joe, but he can't find the tickets, so she invites him back to her boarding house for supper. Surrounded by the other, middle-aged, tenants, they spend an awkward evening together, and when they are finally left alone Sally laughs off Joe's compliments and avoids him by playing the piano. Joe's displeasure and Sally's relief are obvious when they are interrupted by the arrival of another elderly tenant. Joe is ushered out by the landlady at 11pm sharp.

The next morning, Joe returns to the boarding house and leaves flowers for Sally. The card on which he'd written 'Wear one of these and give me hope' falls out, and Sally arrives at work with a flower in her buttonhole, unwittingly giving Joe the impression that she feels the same about him. Joe happily cuts customers' hair until he sees Sally flirting with Harry, who in the following days comes in as often as possible in order to see Sally, showing her pictures of a farm he has just bought on Dartmoor.

Joe overhears Harry inviting Sally to the cinema, and sneaks into a seat in the row behind them at that evening's performance. The band plays along with the Harold Lloyd short before the main feature, the audience all laughing except Joe. The talking picture comes on and Joe's rage builds as he watches Sally and Harry, remembering their first meeting in the barbershop and fantasising about ravishing Sally and murdering Harry.

Harry takes Sally home and gives her an engagement ring, which she accepts. They kiss, and Joe watches Harry leave. The next day he listens to colleagues gossip about Sally's romance; she arrives and proudly displays her engagement ring. Harry arrives and, oblivious to Joe's fraying temper, asks for a shave and a manicure. Joe finally snaps and cuts Harry's throat, but does not kill him; a policeman is called. Joe threatens to come back and finish off both Harry and Sally.

Having escaped from prison some time later, Joe confronts Sally, who is now living with Harry on his farm. She tries to run away but they are interrupted by guards from the prison checking she is unharmed; Joe is about to give himself up, but Sally refuses to turn him in even when the guards tell her he was on his way to kill her. Pretending everything is fine, she lets the guards in to keep watch. Harry comes home and loads his gun. Sally goes up to the baby's room where Joe is hiding; he asks her to forgive him. Harry comes upstairs and sees Joe, but agrees not to alert the guards for Sally's sake, distracting them so Joe can escape onto the moor, wearing a coat Sally gave him. Joe gets away, but finds a picture of Sally that she put in the coat pocket. He runs back to the cottage but is shot by the guards, and dies in Sally's arms.