The third novel in a WWI alternate history series where America's greatest weapon against Germany is the Black Chamber, secret agent Luz O'Malley, and technical genius Ciara Whelan. Only they can protect America's best hope of winning the war. The Great War is at a stalemate, and the only thing stopping Germany from striking America is the threat of the United States using their own Annihilation Gas against them. But America's supply is quickly decaying...