As the people and businesses of London are quickly recovering from the ravages of the plague, in Westminster, plans are afoot for a grandiose ball in honour of a long-dead but English-born Pope. Meanwhile, the markets and coffee houses in the city are awash with rumours of war and portents of a coming disaster. Mysterious killings at both ends of the capital have been caused by an unusually long, slender blade, and Thomas Chaloner is ordered to investigate. This leads him into a tapestry of conspiracy, outlandish claims of the Second Coming, the reappearance of a number of regicides and ever more brazen killings. As the date of the great ball looms closer, Chaloner fears that there is a dangerously credible conspiracy against the throne, and he has very little time to prevent history from repeating itself.