After his family relocates from London to rural Devon, sullen British teen Tom (Freddie Cunliffe) spends most of his time moping about the house. When he inadvertently discovers an incestuous relationship between his older sister, Jessie (Lara Belmont), and their father (Ray Winstone), the revelation threatens to have dire consequences. The mother of the family (Tilda Swinton), unaware of the dark secret, has recently given birth, and the siblings must contend with the harrowing situation.