Oliver Pope is driving home on a rainy day. Distracted by concerns about work, he hits a paperboy on his bicycle. Oliver gets out of the car and glances at his victim, and then goes back to his car and drives off as a woman sees him from a distant and calls to him to stop.
Oliver returns home and his wife Lillian wonders why he parked it in the garage when they were going to go out. He says that he has a headache and complains about how Pete Radcliff, one of his co-workers, is after his job. When she suggests that Pete isn’t like that, Oliver angrily accuses her of always arguing with him. Lillian gets him some medicine but Oliver complains that he doesn’t feel well. When she glances out at the garage, she tells her husband that someone is fooling around in there. Oliver investigates and discovers that the ignition is on and the headlights on his car are flickering on and off on their own. He turns off the ignition and goes back inside, and tells Lillian that there must be some faulty wiring. She points out that they just had the car repaired and there shouldn’t be any problems. Lillian then asks if he saw the newspaper, and complains that the paperboy is late.
Later, Oliver privately calls the hospital to ask about the boy, claiming to be a friend of the family. He’s informed that the boy is badly injured and likely won’t survive.
Oliver and Lillian go to bed, but his car horn goes off in the middle of the night. He goes to investigate but finds no one in the car. He opens the hood and yanks out the cables, and the hood slams down, almost hitting him.
The next morning, Lillian reads the newspaper article about the paperboy and hopes that the man responsible gets what he deserves. When Oliver wonders how she knows it was a man, Lillian says that a woman saw the driver. He tells her that he’s not feeling well and won’t be going to work. The horn goes off again and Lillian drives the car to the garage. It stops in the middle of traffic.
When Lillian returns home, she tells Oliver what happened, and that the car stopped at the same intersection where the paperboy was hit. The police were watching the intersection to see if the hit-and-run driver returns to the scene of the crime, and told Lillian that they’re close to making an arrest. Lillian tells Oliver that the car is at the repair shop, but then the horn goes off. The couple investigates and is surprised to see that the car is back in the garage.
The garage calls and asks if Oliver picked up the car. They say that they didn’t deliver it. Oliver asks Lillian how it got there. The doorbell rings again and Oliver tells Lillian to answer it and to say that he’s not there. Oliver lies down on the couch and pretends to be ill as his co-worker, Pete, comes in. He explains that he decided to clear out Oliver’s in-box and help him out. Oliver takes offense and snaps at him, and Pete snaps back. As he goes, he apologizes and says that the paperboy was a neighbor kid that played with Pete’s kids. Lillian asks the boy is doing and Pete tells her that the paperboy died an hour ago.
A policeman watches the intersection with the female witness, hoping the hit-and-run driver will come by again. She tells the officer that a passing car is the one she saw, and he pulls it over. Pete is driving, and the officer informs him that they have a witness identifying him as the killer.
The next day, Oliver reads about Pete’s arrest, and Lillian insists that Pete couldn’t have done it despite the eyewitness’ claim. Oliver says that he knows her better than she does, and that he doesn’t have to worry about his job now that Pete is in jail. Lillian hears a noise from the garage and wants Oliver to investigate. When she threatens to call the police if he doesn’t, Oliver goes out. The front fender falls off the car and the car starts up on its own. Panicking, Oliver runs back into the house.
That night, Lillian is asleep when she hears loud music playing from the neighbors. She wakes up Oliver, who calls out without getting a response. He goes to the garage on his way out and the radio plays a news broadcast about Pete’s arrest and the paperboys’ funeral. Oliver turns off the radio but it starts up again on its own, playing the same broadcast. Oliver smashes the radio and then knocks out the headlights when they start flashing on and off. As he goes inside, the horn goes off and he pops the hood and smashes the mechanism.
The next morning, Oliver dresses for work. Lillian insists that he call the police about the prowler in the garage, and he promises to put a lock on the garage that night. As he leaves, he admits that he’s going to take the bus and plans to sell the car. As Oliver walks down the sidewalk, the garage door opens on its own and the car pulls out and drives down the street on its own. It pulls up next to Oliver, who starts walking fast to get away while avoiding attention. Finally he retreats and runs down between the houses. As it starts to rain, the car cuts Harry off and follows him down the street. He finally slips on the wet pavement and the car stops inches from his head. The passenger side door opens and Oliver, realizing that there’s no escape, gets in. The car drives him to the police station to face justice.