In the court of King George IV, Major Mearns---an old dog of war and veteran of Willington's army---is the guardian of Windsor Castle. Some would call him a spy; he calls himself a 'watcher.' Working with his close friend, the resourceful Sergeant Denny, the pair maintain a cool facade behind which they go about their duties quietly and unnoticed.
Unnoticed, that is, until the day Mearns receives a parcel containing a gruesome surprise: a pair of severed human legs. The legs belong to a fellow soldier. Casting aside official protocol, Mearns and Denny decide to investigate the murder themselves, also enrolling the help of a precocious young runaway, Charlie. But soon these maverick investigators find themselves up against all manner of obstacles and danger, not the least of which is the Crown Keepers of the Peace---a unit of former soldiers headed by Mearns's nemesis, Felix Ferguson.
With more butchered body parts turning up in parcels and the number of deaths rising, our amateur investigators find themselves up to their necks in corruption and intrigue. Mearns struggles to keep Ferguson at bay, not only during the investigation, but also for the affections of the desirable Mindy, a maidservant in the castle. With the pressure on, can Mearns get to the bottom of the murders and win the heart of his ladylove?