London, 1656: Captain Seeker is back in the city, on the trail of an assassin preparing to strike at the heart of Oliver Cromwell's fragile Republic. Yet in this fourth adventure (after Destroying Angel), Seeker is also preoccupied by the horrifying discovery in an illegal gambling den of the body of a man ravaged by what is unmistakably a bear. Accompanied by spy Thomas Faithly, Seeker follows a trail that leads to the desolate Lambeth Marshes. When the two threads of the investigation begin to join, Seeker realizes just who he is up against. The Royalists in exile have sent to London their finest mind and greatest fighter, a man who will stop at nothing to ensure the Restoration. Has Seeker finally met his match?