The Sleeping and the Dead — Ann Cleeves

Peter Porteous fled the pressures of big city crime to be a small town cop ...

But he soon finds out there's no getting away from murder. When water levels drop in a summer drought, Cranwell Lake reveals a thirty-year-old secret -- a body stabbed in the back with an anchor tied around its waist. Detective Chief Inspector Porteous soon identifies the body as missing teenager Michael Grey. But that's only the start of the mystery.

Fifty miles away, prison librarian Hannah Morton is about to get the shock of her life. For Michael was her boyfriend, and she was with him the night he disappeared. The grisly discovery brings back dreaded and long-buried memories from her past and begins a deadly chain of events ...