Margaret Hall (Tilda Swinton) is a lonely Lake Tahoe housewife whose naval officer husband spends months at sea on an aircraft carrier. In his absence, Margaret does her best to do right by her family, no matter what. So when her eldest son's lover washers up on the beachfront in front of their house, she does the only thing an unflinchingly devoted mother could: she hides the body to protect her son. What begins as a riveting cat-and-mouse game soon turns into a haunting love story with self-sacrifice at its center. For, as Margaret attempts to dodge blackmail, the law and even the questions of her family, she herself becomes exposed.