Margaret Hall lives in California in a large house on the shores of Lake Tahoe, with her adolescent son Beau and her father-in-law. Her husband is a pilot and is always away travelling. Margaret discovers that Beau has had a fling with a certain Darby Reese, a man in his thirties with a dubious reputation who owns a nightclub in the neighbouring city of Reno. Beau and Darby have even had a minor car accident while driving together in a state of drunkenness. Margaret is shocked (by their homosexuality or by the situation?), and tries to get involved in the relationship, prohibiting Darby from having contact with her son, but the young man does not want to be controlled: he will see Beau again, and his decision will have disastrous consequences for all of them... This is a passionate thriller, with the lake as the threatening background image and with an insuperable Tilda Swinton in her role as a woman pushed by fear through an unstoppable course of events.