In New York City, Ms. Daigle, a teacher, returns home to her apartment in a dark and depressing building. Her landlord Mr. Johnson tells her that a master key is missing and that all the locks will have to be replaced. Ms. Daigle goes in her apartment to find Ann missing, and there is a note saying she had to leave. Brad is in bed and has some sort of disability, so he needs to be taken care of. Once Ms. Daigle has done what she needs to for Brad, she grades papers with a red pencil. A camera shows Brad's room. An image appears on the screen and then disappears. Brad starts yelling and Ms. Daigle goes in his room to find him holding a bunch of keys which he won't let go of. Then Ms. Daigle is attacked several times and stabbed with her red pencils.Phil arrives at the building with his moody 14-year-old daughter Violet and his 7-year-old daughter Rose. He checks in with Cal and tells the girls to wait in the lobby. Phil tells Mr. Johnson he is applying for the job as super because he wants to be able to spend time with his daughters now that their mother is deceased, and that being a cop was too risky, since they have already lost one parent. Mr. Johnson explains that the building was a savings and loan that failed during the Depression, and it has a mix of luxury apartments whose residents can take advantage of a gym and other amenities, and low-income apartments. There are multiple basement floors which are like a maze, and a furnace that dates to the 1890s. In the lobby, mean old Mrs. Grey, who has a small yappy dog, is pleased to see Violet reading George Bernard Shaw. Rose, playing with a toy with tiny silver balls that are supposed to go in a clown's mouth, gets bored and starts looking around. Violet also disappears and she meets Vondell, who is about her age and lets her have a cigarette. Rose goes downstairs to the furnace, which fascinates her, and a creepy janitor named Walter tells her she shouldn't be there.When he is finished with Mr. Johnson, Phil wonders where his girls are. Beverly, a pretty blonde woman, says she saw Violet. When he finds her and Vondell, Phil chastises Violet for smoking. The family moves into what must be the worst apartment in the entire building, but Phil says it's only temporary. As usual, Violet is unhappy but she's unhappy about everything. And the murder victim was her favorite teacher.Mrs. Grey hears a noise and takes a knife when she goes to investigate. There is a pleasant lullaby and she disappears.Phil is taking out the trash and sees the bag from Ms. Daigle's apartment with broken red pencils. Then he meets Julio, one of the other building employees, who says Phil can take what he wants to furnish his apartment and helps him move in some furniture. So far there is no bed, but Rose ends up getting the first bed, leaving Violet and her father still sleeping on the floor. When they see Beverly out for a run, Julio says his wife works for her at a museum. However, Julio hits on other women.Vondell is too busy to answer the door but his mother is fixing a meal and tells him to answer the door anyway. Vondell goes out into the hall and asks someone why they are there, and he too disappears. Vondell's mother is upset that her son is missing. Soon, the missing people in the building are making the news.Phil has several encounters with Walter, whose creepy behavior around his girls annoys Phil, and Phil threatens Walter. Eventually, Phil attacks Walter, then he wakes up. Then Rose can't sleep and she wakes up her father. They go visit the furnace.Mr. Johnson tells Cal there have been complaints about the noise Mrs. Grey's dog is making. Cal says Mrs. Grey will have him fired if she goes in her apartment. Mr. Johnson says Mrs. Grey has been in that apartment 50 years paying next to nothing and he doesn't care. Cal and Mr. Johnson find the dog but no Mrs. Grey, and her cane is still there.Rose is happy that her family gets to take care of the dog.Phil starts spending time with Beverly and they learn about each other. Beverly says she understands Violet because her father had connections and was able to get custody or her and her sister and cut them off from her mother.Phil's family attends a party and meets Julio's wife and kids. Rose is disappointed when they have to leave the party early. Rose loses her bed after it is discovered Walter put something dirty in it.Ms. Daigle's apartment is much nicer than it was as two women prepare to rent it. Julio notices there is still blood on the floor but Mr. Johnson uses a machine to clean it up before anyone can see it.Violet gets in the elevator and it gets stuck. Walter's apartment has numerous screens that let him watch what is going on in the building, and he is able to restart the elevator. Violet gets out on a very dark floor.Fed up with Walter's behavior toward his girls, Phil plants a piece of Mrs. Gray's cane in Walter's apartment and makes an anonymous call to the police. There are numerous religious items. Phil believes enough evidence will be found that Walter can be arrested for the murder. Walter is arrested, but he is soon released.Mr. Johnson exits the mechanical room and tells Phil he shouldn't go in there because that's not part of his job.Phil starts to suspect Mr. Johnson is getting rid of people in rent-control apartments so he can bring in people who can pay more.Phil and Beverly spend more time together and Phil tells Beverly how he saved Rose when their home burned but couldn't get to his wife in time. Violet was outside.A pretty female employee of Mr. Johnson gets Phil to go fix something, leaving Julio to watch Phil's girls. In fact, Julio and the woman go into a room and do something else.Julio goes in Phil's apartment and lets the dog out of its cage. He sees a ball and wants to know why a ball that belonged to Vondell is in Phil's apartment. When he sees Rose, he says he never met Rose before. Rose explains no one sees her until it is time. One of the silver balls goes into the clown's mouth, the lullaby plays, and Julio is killed.Mr. Johnson confronts Phil when he learns the police department he claims to have worked for never heard of him. Then Mr. Johnson is killed.Violet needs someone to talk to, and as she spends time with Beverly, at long last she seems happy. Violet shows Beverly photos on her phone. Beverly sees a photo that looks like Rose, but it's actually Violet from seven years earlier. Beverly has never actually seen Rose, but Violet explains that she and Rose were twins and Rose was always the one who got what she wanted. One day she got angry and set the house on fire, and she was killed. Rose claims her father broke her neck and threw her out the window. Beverly realizes she and Violet are in danger and they start running, ending up in Walter's apartment.Phil has another fight with Walter, and it appears Walter might have died, but he eventually comes back, throws something at Rose that stops her from moving, and makes a circle around Rose which he sets on fire.Rose is rescued, and Beverly fears she will be the next victim, but Rose says she wants a mommy. Beverly is willing to join the family, and they walk through the lobby. The audience sees four people, and Cal only sees three.