Someone is killing Britain's warlocks. Twenty-two years after the Second World War, a precarious balance of power maintains the peace between Great Britain and the USSR. For decades, the warlocks have been all that stand between the British Empire and the Soviet Union—a vast domain stretching from the Pacific Ocean to the shores of the English Channel. But now each death is another blow to Britain's security. Meanwhile, a brother and sister escape from a top-secret research facility deep behind the Iron Curtain. Once subjects of a twisted Nazi experiment to imbue ordinary humans with extraordinary abilities, then prisoners of war in the vast Soviet effort to reverse engineer the Nazi technology, they head for England. Because that's where former spy Raybould Marsh lives. And Gretel, the mad seer, has plans for him. As Marsh is drawn back into the world of Milkweed, he discovers that Britain's darkest acts didn't end with the war. And as he strives to protect Queen and country, he's forced to confront his own willingness to accept victory at any cost.