The Powder of Death opens with a returned envoy to China meeting an English scholar in Oxford in the mid-13th century to share a deadly secret. They vow that the knowledge of gunpowder must die with them as the consequences otherwise are too terrible to contemplate. The novel tells the story of its re-discovery, one man's obsession with the powder of death, and Edward III's determination to use it to his advantage. He does so at the Battle of Crecy, the first full-scale battle at which guns are deployed in the field. The nature of warfare is changed forever, and the world hears the death-knell of Knightly chivalry.