George and his younger French wife, Teresa, live in a secluded British castle on a tidal island. Their mundane existence is shattered when two wounded gangsters, Richard and Albert, seek refuge in their remote home after a failed heist. Richard, the more brutish of the two, intimidates the couple and forces them into compliance, while Albert is critically injured and bedridden. George, a timid and neurotic man, finds himself powerless under Richard's oppressive presence, and Teresa's primary concern is her own safety and amusement.

As the situation becomes increasingly tense, Richard's domineering behavior escalates, revealing the growing psychological strain on everyone involved. George and Teresa’s relationship starts to fray under the pressure, exposing underlying resentments and tensions. The isolated setting magnifies the characters' paranoia and desperation, creating a suffocating atmosphere of dread. The couple struggles to find a way out of the predicament, with Richard constantly watching their every move. In this volatile environment, the dynamic between captors and captives shifts unpredictably, leading to an inevitable confrontation.