Kirsten Schwarz (Eleanor Tomlinson), a 17 year old girl going on 18 in four days. She is an insomniac. In internet, she finds the legend of a village called Selmen, where many female teenagers commit suicide the day they become legally adults. Her sister, disastrous Marie Schwarz (Finn Atkins) tells her that she's left her job, and that she needs help finding another one. Through the net, Kirsten finds images of the cemetery and the eerie face of a young lady, which we would later know that it's Hepzibah (Markéta Frösslová). Kristen also checks her email and gets a surprise: her parents say that she's old enough to know that she's adopted, and that her biological father is alive. Marie knew that Kirsten was adopted, but she thought both her parents had died in a car accident.
Kirsten decides to go to Selmen to see what happens there. She talks to Dr. Wagner (David Bamber) who tries to convince her of taking some experimental pills of his invention to make her sleep. She also talks to Melanie (Helen Mutch), who is in the same situation as her. She mentions other cases like Stephanie (Emily Cox), whose parents will not leave her alone to prevent her committing suicide. A seance is organized to communicate with the spirits the night Melanie is 18, and she kind of communicates with a spirit that Kristen's has the intuition that goes by the name of Hepzibah. The girl's boyfriend behaves like a sexed-up brat, kidding around with the ouija and then leaving her alone when she refuses him sex. At that moment, the girl hears a baby crying. She tries to follow the sound inside her walk-in closet, and that is the place where Hepzebah attacks her, hanging her so that it looks like she's committed suicide.
Stephanie's case is even worse. Her parents tie her down on her birthday to prevent her from committing suicide. Their daughter pledges with her: if they tie her down, the witch will catch her, but nothing can convince their parents. At 12:00, exactly when her birthday begins, the teenager has a bad dream. She wakes up in a derelict hay cottage somewhere and Hepzibah hangs her in a noose. Her parents scream when they find her dead body hanged - supossedly having committed suicide.
Kristen is nice to an old librarian (Murray Melvin). She steals from the library a book on local witchcraft, Hepzibah's diary, in which she tells of how she used to help villagers with traditional natural remedies. However, one of the village daughters accused her of witchcraft. Hepzibah was burnt at the stake, and Joseph Curwen (Micahel Devera) did not try to protect her of their son. In fact, he was present at the court who condemned her.
Kristen is helped by Raphael (Christopher Elson) a young male teenager who had seen the witch materialize in the co-pilot seat of his truck. They also talk with Pater Raymond (Kevin Colson), who doesn't believe her. Kristen thinks that Hepzibah wants to be buried in sacred land to rest forever, but Raymond tells her that she's already buried in secret land - so it has to be that Hepzibah wants to reunite with her baby. Kristen looks for the baby in the surrounding woods.
Marie appears out of the blue. She pretends to take Kristen's back, or to help her anyway she can. Marie can't believe the witch thing, and checks her out from her nasty hostel to a rented house. However, soon Kristen discovers that Marie has reached an agreement with Hepzebah. The witch always takes teenagers in groups of nine, and Kristen will the the ninth; Marie wants to get rid of her parents' favourite daughter, the nice girl who can't do anything wrong, by letting the witch kill her. That will give her a new beginning, supporting her parents through the ordeal and offering them consolation.
The witch appears when Kristen finds the charred body of a baby. With Marie attacking her with an axe, because she wants to kill her and be the one who gives the baby to Hepzibah. Kristens bangs and bangs on the door of the local church until Pater Raymond opens the railing for her. Raphael is badly hurt, the same as Marie
Pater Raymond tenderly wraps together Hepzibah's and the baby's remains, blessing them together so they can rest, and also asks God to forgive the Church, as the priests didn't know what they were doing. Kristen hopes that this will end the omen of the village.
Raphael is in hospital, deeply wounded. He offers consolation to Kristen, saying that it doesn't matter if she hasn't learned the name of his real parent - but behind her, it's the doctor who offered her the drugs, frozen like in a trance, suggesting that he was his secret biological father.
At an institute of Art, two sculptures seem to move when the young lady artist is checking Selmen on the net. She checks around the warehouse, but there is nothing or anyone. Suddenly, on the computer, there is a close-up of Hepzibah's face, smiling menacingly.