Newly promoted Detective Chief Inspector Kathy Kolla investigates a series of brutal murders on Hampstead Heath. Under intense pressure to find answers, she arrests the unlikely figure of Charles Pettigrew, a failing London publisher who lives alone on the edge of the Heath. Pettigrew's lawyer calls on recently retired David Brock for advice, and soon, unable to resist the pull of investigation, the old colleagues, Brock and Kolla, are at loggerheads. At the heart of the gripping mystery of the Hampstead murders lies a manuscript of an unknown novel by one of the greatest literary figures of the 20th century. Brock believes that its story will unlock the puzzle, but how?