Timmy, a third-grade boy, goes to bed every night only after turning on the night light and checking the closet and under the bed. He then says his prayers before going to sleep.
The next day, Timmy is examining a potato bug that he has in a jar when his stepfather, Biff, comes in and tosses a football at him. It hits the jar and breaks it, and Biff tells Timmy to come outside and play football with him and learn how to be a man. When Timmy refuses, Biff tells him that he's a wussy and orders him to clean up the broken jar. Biff goes out to the kitchen to get a beer and Helen, Timmy's mother comes in. She sees the broken jar and Timmy claims that he broke it.
Later, Biff finds Timmy practices the piano and invites him to listen to football on the radio. He half-heartedly apologizes for not being around, since he's at sea working for a living most of the time. Timmy excuses himself, claiming that he has homework, and quickly leaves. That night, he goes through his nightly ritual and starts to say his prayers. Helen and Biff are arguing in their bedroom and Biff is complaining that Helen is turning Timmy into a wussy. Timmy prays to God, blessing everyone... including Biff, eventually. As he tries to get to sleep, Timmy doesn't realize that a creature, the Boogie Man, is watching him from the closet. It quickly closes the door as Helen comes in to tuck Timmy in. Timmy wonders if Biff really loves her and she says that Biff does and he just doesn't understand kids. She sings a lullaby to Timmy and then leaves, while an octopus under the bed blinks its glowing eyes.
At Christmas, Biff, Helen, and Timmy are opening presents. Biff gives Timmy a toy rifle, but the boy is overjoyed when Helen gives him a stuffed panda bear. He runs over to hug his mother while a disgusted Biff looks on.
That night, Timmy goes through his evening ritual but this time a basketball falls out of the closet, startling him. He nervously closes the door, unaware that the Boogie Man is hiding behind his clothes. As he kneels to pray, the octopus reaches out and tries to grab him. Timmy jumps into his bed and hears Biff arguing with Helen again about how she's spoiling Timmy and treating him like a girl. The boy says his prayers and leaves off biff this time, and tries to get to sleep. His stuffed panda starts rocking on the rocking chair and the Boogie Man opens the closet door and glares out at Timmy.
Timmy knocks a stuffed animal off the bed, and a buzz saw spins across the room, threatening him. Timmy yells for Helen, asking for a drink of water. Biff yells back, telling him to get it himself. Timmy jumps onto the floor and the octopus tries to grab him. The Boogie Man jumps out of the closet and Timmy jumps into his bed, screaming. Helen comes to the door and the monsters all quickly hide. She tells Timmy not to create a scene and goes back to her bedroom.
Once Timmy's mother is gone, the monsters come out again. Timmy fights off the buzz saw and the octopus, but the Boogie Man comes for the boy. However, he hides in the closet again when Helen comes in with water. She asks Timmy to be patient with Biff and sings her son a lullaby, and then says that she has to go over to the neighbors to deliver some presents.
Helen drives off and a drunken Biff comes in and offers Timmy a drink of his beer. Timmy spits it out, choking, and Biff starts singing, calling his stepson a coward. Once Biff staggers out, the toys come to life, taunting Timmy and calling him a coward. The monsters come out again but Timmy finally has enough and yells at all of them to leave him alone. They all retreat, the Boogie Man cowering back from the boy's anger.
Biff yells at Timmy to be quiet, and Timmy goes to his bathroom down the hall. He finds a horrible witch waiting for him, cackling. Timmy tries to slip through the living room to go to his parents' bathroom, but Biff sees him and tells him to use his own bathroom. He doesn't believe it when Timmy says that there's a witch in his bedroom, and tells his stepson that he's through coddling him. When he tells Timmy that he's weak just like his mother, Timmy angrily tells his stepfather that he's the weak one. Biff gets out a Ping-Pong paddle and tells Timmy that he's going to spank him, and the boy runs to his room.
When Biff enters Timmy's bedroom, he yanks away the sheets and prepares to spank the boy. However, the witch comes in and breaks Biff's neck. The body falls to the floor and the octopus and the buzz saw move in on it while Timmy watches in satisfaction.
A few days later, Timmy's aunt and grandmother come over after the funeral. When Timmy's Aunt Teresa expresses surprise that Biff died of what appeared to be a heart attack, Timmy tells them that the monsters got Biff because he was scared. Helen orders her son to his room and Timmy goes to the room. On his door he has a sign warning about the monsters in his room.