February 1381. London lies frozen in the grip of one of the bitterest winters on record. The ever-rising taxes demanded by the Regent, John of Gaunt, are causing increasing resentment among the city's poor. When the seething unrest boils over into a bloody massacre at a splendid Southwark tavern, in which nine people, including Gaunt's tax collectors, their military escort and the prostitutes entertaining them, are brutally murdered, the furious Regent orders Brother Athelstan to get to the bottom of the matter.