Nan Adams first appears when her vehicle goes off the road of a Pennsylvania Turnpike after a bad accident. A mechanic puts a spare tire on her car and directs her to the nearest town to fix it properly. Just before she leaves, Nan looks across the road and sees a man hitchhiking that wasn't there before. Unnerved, she drives away quickly. As she continues her trip, Nan sees the same hitchhiker thumbing for a ride at several other points on her journey. 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 hitchhiker is trying to kill her. She continues to drive, becoming more and more afraid, stopping only when necessary; but every time she does, the same hitchhiker is there.
When she ends up stranded in New Mexico, she meets a sailor on his way back to San Diego from leave. Eager for protection from the hitchhiker she's been seeing, she offers to drive the sailor to San Diego herself. However, she is still paranoid about the hitchhiker, and when she sees him on the road she 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. 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 hitchhiker is not a man who wants her to die, but is rather death, patiently and persistently waiting for her to realize that she has been dead all along.
Nan returns to the car and sees the hitchhiker's face in the reflection of the vanity mirror on the visor instead of her own face, and accepts her fate.
- She was named after one of Rod Serling's daughters.