Southern England, 1964. Unease descends upon a small coastal town when a young woman, Margaret, returns from a two year stay at a psychiatric institution. The town’s residents are convinced Margaret is dangerous and accuse her of murder. Amidst her parents’ hopeless attempts to carry on as if nothing ever happened, Margaret reaches out to her younger sister Annie for solace. In turn, Annie is reluctant to approach her sister and seems to be withholding some information from their parents. As her deep seated guilt accumulates, Annie must gather the courage to confront the horrible past event that tore her and Margaret apart all those years ago.