Apothecary John Rawlings and his wife, Emilia, are delighted and honoured to be invited to a Christmas Mask gathering to be held in the grounds of Gunnersbury House, hosted by Princess Amelia, a close relation of King George II. Excited by the sense of occasion, and by her first large formal gathering since the birth of their infant daughter, Emilia spends a long time choosing and refining her costume for the ball.

Once at Gunnersbury House, the event is everything the Apothecary and his wife could have wished for and John Rawlings considers Emilia the belle of the ball in her fetching red cloak to keep out the December chill. After talking to friends he catches sight of her heading outside, and follows to spend some time walking with her through the magnificent grounds. Tragically, when he finds Emilia she is bleeding to death after being stabbed through the heart.

Stricken with grief, John Rawlings is numb. But when his former friends, the Blind Beak and Joe Jago, enforcers in law, are ordered to arrest him as the prime suspect, the Apothecary flees to Devon to seek help from an old ally. Discovering the identity of his wife’s murderer is crucial, not just to see Justice served, but to save his own neck from the gallows…