As David (Alan Rickman) and Alexis Weinberg (Polly Walker) race through a torrential rainstorm to get the last ferry to their private island, they catch sight of an injured young man (Norman Reedus) at the side of the road. The mysterious stranger reluctantly accepts their help and by morning the incident is virtually forgotten, until a series of coincidences leads him back into their lives and into their home. As events slowly unfold at the isolated retreat, what began as an act of kindness slowly gives way to a bizarre love triangle that ultimately forces the couple into a frightening spiral of sex and betrayal, where nothing is what it seems.