Set in their family estate, Starve Acre, in rural 1970s England, Richard and Juliette find their idyllic family life disrupted when their son Ewan starts acting strangely. The formerly happy couple grow farther apart when Richard buries himself in local folklore -— including the myth that an ancient oak tree set on their estate possesses phenomenal powers — while Juliette seeks comfort in their local community. Just when it seems the couple may reconnect, dark and sinister forces find their way into the family home and their attention is diverted by an unexpected discovery.