Amy Mustafi moves into an isolated mansion in the British countryside under the instruction of her controlling husband Shayan, while he ties up a business deal abroad. 

A housekeeper and her young brother are engaged to help Amy run the estate. However, Amy soon finds a sealed off entrance to the former servants’ quarters of the house. Upon opening the long-forgotten door, Amy soon discovers the house has guarded a mystery for over a century. 

Fuelled by loneliness and insecurity, she becomes obsessed with investigating the house’s past. In doing so, she begins to experience supernatural phenomena as she spirals into psychological turmoil. Is there something else at WinterstokeHouse with Amy?  Or is it all a phantasm borne out of Amy's dangerous mind?