Plot
In an isolated, windowless boarding school called Vestalis, run with strict military precision, girls live on numbered levels and are taught to follow the "feminine virtues" of obedience, cleanliness, patience, gentleness, humility, loyalty and modesty while avoiding "vices" such as anger, curiosity and sentimentality. They are told that the school protects them from the toxic outside air and that their lessons prepare them for adoption by members of high society, who only want the girls if they are "clean." Breaking the rules results in being taken downstairs for punishment, which all of them universally fear. Best friends, Sophia and Vivien, line up with the other girls on Level 10 to wash their faces in front of a camera in an allotted, regimented time. Vivien steps out of line to help Sophia, who dropped her jar of face cream, and in doing so exceeds her time limit. The guards arrive and Vivien is dragged away, crying and screaming in terror.
Years later, Vivien and others are moved to Level 16 (the final level). She reunites with Sophia for the first time since Level 10. Sophia warns her not to take the daily vitamins, which are actually powerful sedatives. That night, while pretending to sleep, Vivien and another girl, Olivia, are carried to a lounge by the guards. There, Miss Brixil, the facility manager, presents them both to an aging couple, who choose Vivien and make plans to purchase her. When they are returned to their dormitory, Vivien manages to escape into the hall, only to find that the outer door requires key card access. Throughout the night, several others are taken to the lounge and subsequently returned. Miss Brixil, talking to an unseen person on the phone, expresses concern about the behavior of a guard, Alex, warning that he should not be allowed around the girls unsupervised.
For their first time ever, the Level 16 girls meet the facility's doctor, Dr. Miro, who informs them that a fever has been going around some of the other halls and gives them a "vaccine." The injection gives them painful arm rashes and causes one girl to have a seizure. He initially acts kind towards Vivien, but when she attempts to share her concerns with him, he injects her with a sedative. Sophia informs Vivien that Alex, the guard Miss Brixil was concerned about, secretly visits the dormitory and "touches" the girls while they sleep. She plans to wait until Alex comes to the dormitory, restrain him, and steal his key card. Shortly afterwards, Ava reports Vivien for unclean behavior and she is locked in a small cage for the night. That night, Sophia attacks Alex when he comes to the dormitory; she steals his key card but is captured before she is able to free Vivien.
Brixil and Miro inform the girls that they were unable to find the key card Sophia stole and ask where she hid it. When they are unable to find it, Rita is taken downstairs for punishment with a warning to the rest that another of them will be punished each day until the card is found. Alone, Brixil and Miro discuss the school's dwindling funds and the pressure being put on them (ostensibly by powerful criminals) to produce results.
During the night, Vivien finds that Sophia hid the key card behind her headboard and escapes, finding and freeing Sophia. They then enter a crude operating room full of corpses, where Rita is found dead, her facial skin removed. Vivien insists they leave immediately, but Sophia refuses to go without the others. While Sophia goes to get them, Vivien finds a video in the lounge revealing that the facility is actually a rejuvenation clinic run by Miro; the girls are raised in a sterile environment, with no exposure to damaging sunlight, so that their facial skin can eventually be transplanted onto rich buyers.
Sophia tries to warn the other girls about their situation, but they are suspicious. Vivien brings Brixil to the rest of the group, where she reveals that Sophia is telling the truth. After locking Brixil in the box, they lead the others out of the facility, closely pursued by the guards. During a fight, Sophia is injured, but the two narrowly escape by hiding in a shed. When the guards can't open the security door, Miro arrives and attempts to deceive Vivien into coming outside and helping him round up the other girls so he can eliminate her for revealing the facility's secrets; he reveals that their birth parents sold them to the facility as babies. Vivien, aware that Miro only cares about her face, cuts herself with the scalpel while a distraught Miro watches. Soon, a group of henchmen lead him away to see their boss, the mastermind of the operation, who orders Miro terminated. A gunshot is heard; Miro has presumably been killed for losing control of the clinic. An exhausted Sophia and Vivien fall asleep inside the shed, awakening the next morning to find the door being broken down by a squad of police officers and emergency service workers, who already saved the other girls, aware of the crimes committed by Miro and Brixil. Sophia and Vivien are led to safety, holding hands while they experience sunlight for the first time.
