June 1939. England is preparing for war. Meanwhile in Germany, Otto Hahn has produced the first man-made fission and the Nazis set up the Uranverein group of physicists: its task is to build a superbomb. At Cambridge's Cavendish Laboratory, where the atom was split in 1932, the British are working on their own bomb. Hitler's generals need to be sure they know all the Cavendish's secrets. Only then will it be safe for Germany to wage war. When one of the Cavendish's finest brains is murdered, Professor Tom Wilde is once more drawn into an intrigue from which there seems no escape. In a conspiracy that stretches from Cambridge to Berlin and from Washington DC to the west coast of Ireland, he faces deadly forces that threaten the fate of the world.