1930s, England. Linus (John Heffernan), his wife Marianne (Jessica Brown Findlay) and their daughter Adelaide move into town, where Linus has been posted as the new reverend. He's been tasked by the Church to renew the villagers' faith, which has been lost after the disappearance of the previous reverend's family, who lived in the very same mysterious manor where Linus and his family have settled into.

Soon after their arrival, strange events start to occur: ghostly voices, dark figures dressed as monks, mysterious totems, and Adelaide's behaviour becoming stranger by the day. It soon becomes clear that a malicious entity seeks to possess Adelaide and that the Church is hiding a terrible secret...

As the menacing spirit grows stronger, Linus and Marianne have to confront their beliefs and enlist the help of Harry Reed, a famous Occultist. Together, they must uncover the terrifying truth about their house and the paranormal force which inhabits it... and hope it isn't already too late for Adelaide.