Paula Grey knows something’s up when a boat vanishes forever in a fog off the British coast and its sole occupant drifts ashore – dead.  Tweed’s suspicions are aroused when he  finds that the daughter of Sir Gerald Andover, an expert on global market trends, has been kidnapped with no ransom demanded. Autocratic Brigadier Burgoyne and amiable Willie Fanshawe live in adjoining houses – what role do they and their glamorous ‘housekeepers’ have in this?  At London Airport, Tweed and foreign correspondent Bob Newman witness the murder of Hilary Vane, arriving from Washington with vital data. The assassin, a woman, escapes. Three more are murdered by the mysterious woman. A British naval commander warns Tweed that vessels are disappearing in the Far East, off Cape Town and the coasts of Germany and Denmark. And unbeknownst to Tweed, two ships, undetectable by radar are sailing on a deadly mission to Denmark.   Who is the shadowy Anne Marie? Who is Vulcan, the British controller of a lethal fifth column? And who is the sinister Doctor Wand, wielder of power from America to the Far East?