Ex-cop Robert and his wife turn their remote Lake District guest house into a safe house. As a family under threat arrive, Robert tries to work out why they are a target.
While the police believe they are closing in on the man hunting David Blackwell and his family, Katy still has her doubts about Robert's methods and questions him further.
Sam and Joe head off across the lake and find themselves caught up in a terrifying ordeal. When events dramatically spiral, it has serious consequences for the family and Robert.