The story begins with a woman, Nan Adams, who has been in a car accident on a cross-country road trip from New York to Los Angeles. A mechanic puts a spare tire on her car, and then leads her to the nearest town to fix it properly. Just before she leaves, she notices a strange-looking man hitchhiking. Unnerved, she drives away quickly. As it turns out, this is the first of many times that she will see the same man, always hitch-hiking and wanting her to pick him up. She becomes increasingly frightened of him, and when she is stuck on a railroad crossing and nearly hit by a train, she becomes convinced that the hitch-hiker is trying to kill her. She continues to drive, becoming more and more afraid, stopping only when necessary; but every time she does, the man is there.
When she ends up stranded in New Mexico, she meets a different man, a sailor on his way back from his leave and returning to his ship in San Diego. Eager for protection from the hitch-hiker she's been seeing, she offers to drive the sailor to San Diego herself. However, she is still paranoid about the hitch-hiker, and when she sees him on the road and tries to run him over, the sailor, who can't see him, begins to fear for her sanity and leaves her. In Arizona, Nan stops to call her mother. However, the woman who answers the phone, Mrs. Whitney, says that Mrs. Adams is in the hospital: She had a nervous breakdown after finding out that her daughter, Nan, was killed in an auto accident in Pennsylvania six days ago, when the car she was driving blew a tire and overturned. At this point, Nan realizes the truth: The hitch-hiker is not a man who wants her to die, but rather, the personification of death itself, just patiently and persistently waiting for her to realize that she has been dead all along.
"I believe you're going...my way?" he inquires from the back seat, almost friendly.
As Nan accepts her fate, Rod Serling narrates the final lines.