Four-part thriller set in the beautiful wilderness of the Lake District. Former detective Robert and his wife Katy are asked by close friend and ex-colleague DCI Mark Maxwell to turn their remote guest house into a safe house. Robert is tempted but will Katy agree? Later, Mark finds himself dealing with a family left reeling from an unexplained assault. David Blackwell has been hospitalised and an innocent passer-by is in a critical condition. Mark needs to find out why this family was targeted and track down the assailant, so he asks Robert and Katy to take David, Ali, Louisa and Joe Blackwell and keep them safe.