After some years of tension, Richard (Clive Owen) begins a sexual relationship with his sister Natalie (Saskia Reeves). Now married, the relationship proves dangerously obsessional. Their private intensity ( working class origins) contrast with the middle-class, inhibited, stuffy public scenes we see in the Richmond world into which Natalie has moved with her marriage. As the guilt and intensity of the siblings increases we seem to be heading for disaster, a forboding which increases when Natalie's husband Sinclair finds out.…