The majority of the story occurs in the office of Dr. Harper, a psychiatrist, where a man named Lester Billings talks to the doctor about the "murders" of his three young children. Billings seems paranoid and possibly schizophrenic as he describes the circumstances of the death of his children. His first two children died mysteriously of apparently unrelated causes (diagnosed as crib death and convulsions, respectively) when left alone in their bedrooms. The only commonalities were that the children cried "Boogeyman!" before being left alone, and the closet door was open slightly after finding their corpses, even though Billings was certain the door was shut.
Billings' wife Rita became pregnant approximately a year after their second child's death, at which time the family was living in a different house far away from the location of the original deaths. Their first year in the new house was without incident, but not long after, Rita left to care for her mother who had become ill. Billings and his son were left alone in the house.
It soon became apparent that whatever had killed the first two children had managed to track down Billings and his family, lingering in the closets for a brief time. Finally one night, the child cried "Boogeyman" while being put to bed, and an hour later, the child began to scream. Billings ran into the son's room and found a demon killing the boy. Billings, terrified, fled to a local 24-hour diner. He returned home at dawn to find the boy on the floor with a broken neck and the closet door open slightly. Billings lied to the police, arguing that the death must have been accidental.
As Billings finishes his story and starts to leave, Harper recommends he make an appointment with the nurse for further discussion. Returning to the office after finding the lobby deserted, Billings finds Harper taking off a mask to reveal that he is in actuality the Boogeyman that had killed his children.