Will Harper is a psychiatrist with a home office who lives with his two daughters,Sadie,a teenager,and Harper,a 9 year old. They are all traumatized by their mother's death in a car accident.A lady psychiatrist Dr.Weller is treating the kids,but Will doesn't take part.One day,a dischevilled man named Lester Billings shows up at Will's office and asks for a session. He says a closet monster stalked his family and killed his 3 little children,Denny,Shirl,and Andy who supposedly died from SIDS and crib death. He has drawings of the creature,and he says his youngest Andy was choked.Will goes downstairs and calls the police, scared and unstable man has gotten into his home.Sadie arrives home early after her friend Bethany brought stuck up Natalie around her in school and Natalie said some unkind remarks and in a shoving match, accidentally soiled her mother's dress which she is wearing. Sadie hears noises. Lester is found hanging by the neck in a closet. Sawyer arrives home from school as ambulance takes his body away,but now the Boogeyman is stalking Will's family. Sawyer is the first to see it creeping at night,and when Sadie puts a string around Sawyer's loose tooth and ties it to a door to yank it out,the door swings opens by itself and takes the girls' tooth off. Sadie is allowed to have a slumber party and she and her friends smoke a little marijuana,then Sadie gets sick and spits up the string and Sawyer's tooth!. The girls have a morbid curiosity to see the closet where Lester hung himself so she shows it to them in her father's study,then she gets trapped in the room and sees the Boogeyman leaping out of the closet,a dark monstrous half human half insect looking thing.She manages to get out of the room and accuses her friends of locking her in,but the girls claim the door wouldn't open. Natalie makes another tactless remark,and Sadie hits her.Natalie says nobody likes her but Bethany and all the girls leave. Sadie now knows Sawyer did see something before. Sadie looks up Lester Billings' family online and has Bethany drive her to Lester's now run down,,filthy,dilapidated house where she finds his widow Rita inside the dark house with no power,having lit it up with candles and flashlights and armed herself with guns and set traps claiming the Boogeyman's weaknesses that it hates light.She says the Boogeyman is behind Sadie and shoots at it. Sadie flees and has Bethany drive her out of there. When the attacks at her home get more frequent and Sawyer is thrown into the wall and has to be taken to the hospital, Sadie knows they're under attack. Her father thinks Sawyer is manifesting this in her mind because they haven't deal with their mother's death. Rita calls Sadie and asks her to come back to the house, then she takes her prisoner to use her as bait in order to trap the Boogeyman. The Boogeyman trips over one of Rita's traps and she shoots at it and flashes the light. The boogeyman is injured but kills Rita,who frees Sadie before she dies. Meanwhile,Will takes Sawyer home and they are attacked by the Boogeyman. Sadie gets home and finds Sawyer locked in the bedroom,surrounded by blinking Christmas lights to ward off the Boogeyman. she lets Sadie in when Sadie proves her identity by remembering that Sawyer once ate too much pizza and got sick at her birthday party.They grab the lights and flashlights and go into the basement where their father has been injured and held prisoner by the Boogeyman. They fight the creature. Sadie has been praying for her mother to make the candle move to the left if her spirit is there,and it finally does.Sadie knows the Boogeyman hates the light so she flashes the flashlight and shoots at it, wounding it. She knows it can be hurt because Rita wounded it back in the house, but the flashlight battery goes out,however with Sawyer's help,Sadie finds gasoline cans,and a flamethrower from the basement and manages to burn the thing to a crisp. Will goes with his kids to a session with Dr. Weller the next day and explains he wasn't sure how to handle things without his wife,but now they're all healing.They head out but Dr Weller asks to speak to Sadie alone.She walks back in but Dr Weller is nowhere to be found and the closet door in her office is half open. Sadie edges toward it nervously. Dr. Weller suddenly appears behind her asking if there's something she can help her with. Sadie shuts the closet door.