Lorraine has a big new challenge: building a team from a collection of staff picked to close down an abandoned asylum and replace it with a new high security unit in isolated Yorkshire. Lorraine has her work cut out for her when it appears that the group includes a secret saboteur. Then, a local teenager is found dead, locked in the isolation room in the derelict asylum building. With a discovery that forces her to face true isolation, trapped in the asylum's tunnels while the demolition team start work above, Lorraine becomes a fresh target for the killer.