The year is 1912. Richard Hannay, a thirty year old Mining Engineer is on his way from South Africa to England on the steamship 'Union Castle'. Whilst on board ship he encounters Lord Haslemere and his beautiful daughter, Lady Anne, and is invited to Lady Anne's coming-of-age party in London.

Upon arriving in England, Hannay tells his good friend Reggie Armitage that whilst working in Rhodesia some months previously, he had been shot and left for dead by Count Von Schwabing and a curious black stone had been left in his right hand. Reggie tells him that five agents, all of them working for Military Intelligence, had been found murdered under similar circumstances.

Hannay finds a mysterious package has been left in his cabin trunk on board the ship, but when he tries to deliver the package he is assaulted and left for dead in a cellar in Limehouse.

During the course of the next day or so Hannay finds himself charged with two murders of which he is innocent, and with the assistance of