One icy cold morning, the remains of a woman are discovered. She has been abused, then butchered. DI Kelly Porter knows this is the work of a monster. One who has killed before - and will do so again.
Kevin Flint is a young man with no friends and a reputation for being odd. He explores the hidden corners of the Lake District, and likes to creep, and watch. He witnesses depravity and it excites him. But will he cross the line from bystander to perpetrator?
Despite her personal life taking unexpected turns, Kelly's detective instincts tell her that the answers lie with Kevin - if only she knew the right questions to ask. Will Kelly miss her chance and have blood on her hands? And will she ever be the same when it's over?