Plot Summary

In January 1974, Valerie accepts a position as a trainee nurse at East London Royal Infirmary. Val befriends Dr. Franklyn and his young patient Saba, but angers the supervising matron by doing so. In response, the matron forces Val to work a night shift during a blackout, even though Val is afraid of the dark.Val befriends fellow nurses Terry and Margaret, but resumes a rivalry with Babs, who used to bully Val when they were both orphans at Our Lady of Grace. Babs continually condescends to Val and brings up a childhood incident where Val supposedly made false abuse allegations against their headmaster. Val also has uncomfortable encounters with Neville, a misogynist custodian who belittlingly sexualizes the nursing staff.Throughout the night, Val detects the smell of burning, notices ash in strange places, and feels a paranormal presence. When she approaches a burned stuffed animal in front of the basement furnace, the presence pulls Val away and pins her against a wall. Val has visions of using her thumbs to blind Babs and of setting Neville on fire.Terry and Margaret help Val recover from being disoriented. Val coughs up creosote. Val tells the two nurses what happened, but Margaret convinces Val to think she only imagined a ghost.Val comforts Saba. Val wonders if the same presence is haunting Saba when she finds a sketchbook of nothing but black scribbles.Val suddenly convulses as she becomes possessed. Saba pulls Val out of her trance. After seeing bruises on Val's neck, Terry abruptly leaves while Margaret continues to gaslight Val. Val stabs her own leg with scissors after becoming possessed again. While unconscious, Val has a nightmare of trying to protect Saba from a ghost only to then strangle Saba herself.When Val recovers, Saba shows her a Polaroid of a previous child patient known as 'Dirty Gail,' whom Val recognizes as the ghost that attacked and possessed her. Margaret insists Gail cannot be a ghost because she merely ran away.Babs shows she is blinded. Accusing Val of being responsible, Margaret locks Val in a closet. Gail's ghost throws Val through a window as Val becomes possessed again. Val warns Saba to stay away from her because she cannot control Gail.On her way to the basement, Val finds Babs's dead body as well as Neville's charred corpse. While resisting haunting visions, Val sees the word "listen" carved into her flesh. Val confronts Gail's ghost. Flashbacks show that Gail was raped and murdered and the hospital staff covered up the scandal.Val recovers in the morning. Saba reveals Gail's ghost helped Saba hide to survive the night. A psychiatric doctor questions Val about the two deaths. Val speculates that Gail's ghost killed them because Neville possibly abused Gail and Babs knew about it. The doctor implies Val has a history of lying. The hospital administrator claims they never had a patient named Gail, which confuses the matron. Val reveals she was pressured into recanting the abuse allegations against her orphanage's headmaster and realizes Gail possessed her because of their similar backgrounds.Val asks Dr. Franklyn to take care of Saba. Val becomes suspicious when Franklyn mentions he will attend to Saba personally. Val discovers Franklyn is Saba's abuser after erasing scribbles from Saba's sketchbook and finding a drawing of the doctor.Val sneaks out of her room and brings Franklyn to the basement for a confrontation. Franklyn punches Val when she disobeys him during a failed seduction. Val cuts the power in an effort to summon Gail, but nothing happens.Franklyn starts strangling Val. Saba interrupts. After again begging for Gail's help, Val levitates while entering another state of possession. Val and Saba both scream at Franklyn. Combining with Gail's energy, a powerful white light develops that kills the doctor.Over the phone, Val warns the hospital administrator to "think of us when it's dark." The matron helps Val and Saba escape. Val is seen fleeing while holding hands with both Saba and Gail. The administrator gets attacked in the darkness. (thanks to culturecrypt)