For decades, Britain's warlocks have been all that stands between the British Empire and the Soviet Union — a vast domain stretching from the Pacific Ocean to the shores of the English Channel. Now each wizard's death is another blow to Britain's national security. Meanwhile, a brother and sister — the subjects of a twisted Nazi experiment to imbue ordinary people with superhuman abilities — escape from a top-secret facility deep behind the Iron Curtain. 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 once again drawn into the world of Milkweed, he discovers that Britain's darkest acts didn't end with the war. And while he strives to protect queen and country, he is forced to confront his own willingness to accept victory at any cost.

The year is 1939. Raybould Marsh and other members of British Intelligence have gathered to watch a damaged reel of film in a darkened room. It appears to show German troops walking through walls, bursting into flames and hurling tanks into the air from afar. If the British are to believe their eyes, a twisted Nazi scientist has been endowing German troops with unnatural, unstoppable powers. And Raybould will be forced to resort to dark methods to hold the impending invasion at bay. But dealing with the occult exacts a price. And that price must be paid in blood. Ian Tregillis' Bitter Seeds is a chilling masterpiece — a tale of a twentieth century like our own and also profoundly different.