London, 1672: A vicious killer stalks the court of Charles II, inscribing his victims' bodies with mysterious markings. Are these the random murders of a madman? The deadly consequence of a personal vendetta? Or the grisly result of a hidden conspiracy? Cambridge, 2008: A Trinity College history professor is found dead, the torn page of a seventeenth-century diary in his hand. His death appears to be an accident, but the college's newest Fellow Claire Donovan and historian Andrew Kent suspect otherwise ...