The majority of the story takes place in a psychiatrist's office, where a man comes to talk about the "murders" of his three young children.
The story's protagonist comes across as paranoid and possibly insane as he describes the circumstances surrounding the death of his children. His first two children die mysteriously of apparently unrelated causes when left alone in their bedrooms. The only commmonality to their deaths is a crack in the closet door that the protagonist is certain he had closed when he left his children.
His wife becomes pregnant approximately a year after their second child's death, at which time the family is living in a different house far away from the location of the original deaths. Their first year in the new house was happy and without incident, but not long after, the protagonist's mother-in-law falls ill. The wife leaves to care for her mother, and the protagonist and his son are left alone. It soon becomes apparent that whatever had killed the first two children has managed to track down the protagonist's new house, and after a brief period of lingering in the closets, this creature (which is now identified as the boogeyman) attacks the protagonist's son.
The father runs into the son's room as the monster is approaching his child, but it's too late to save his son. He flees to a local 24 hour diner. As the man finishes his story, the psychologist recommends he make an appointment for further discussion, but upon entering the lobby, the protagonist finds it deserted. Returning to the room in which he told his story, the protagonist finds the psychologist taking off a mask to reveal that he is in actuality the boogeyman that had killed his children.