Summer 1381. The Great Revolt has been crushed. Brother Athelstan meanwhile is preparing for a pilgrimage to St Thomas Becket's shrine in Canterbury to give thanks for the wellbeing of his congregation after the violent rebellion. But preparations are disrupted when Athelstan is summoned to the scene of a brutal triple murder. One of the victims was the chief clerk of the Secret Chancery of John of Gaunt. Could this be an act of revenge by the Upright Men? At the same time Athelstan is receiving menacing messages from an assassin who calls himself Azrael, the Angel of Death. Could Athelstan's pilgrimage be leading him into a deadly trap?