DI Gilbert Markham and DS Noakes are back, investigating a series of horrific murders connected with a local psychiatric facility in a case which comes uncomfortably close to home. When his team is tasked with solving the mystery of patients who have gone missing from the Newman Hospital, Markham uncovers corruption in high places and a conspiracy of silence. It is only after four deaths and a shocking stand-off, which sees their colleague DS Kate Burton in peril of her life, that Markham and Noakes discover the chilling truth.