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 John Pettigrew, a failing London publisher who lives alone on the edge of the Heath. <br/> <br/>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.<br/> <br/>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 twentieth century. Brock believes that its story will unlock the puzzle, but how?