In Barrington House, a respectable house in a prestigious area of London, there is apartment number 16. No one enters it, no one leaves it, and this has been the case for 50 years. But one day April, a young American woman who was left an inheritance by her great-aunt Lillian, arrives here. According to rumors, towards the end of her life she went mad, but her diary tells a different story: Lillian encountered something terrifying and inexplicable, and it still lives in this house. Deciding to find out the story of her relative, April has no idea what forces she will have to face. After all, Barrington House is not a haunted mansion, and apartment number 16 is not an ordinary cursed place. It is a gateway to something beyond human understanding.