Following the murder of two cabinet ministers, in whom he had confided his fears, Colonel Scudder (John Mills), from British Intelligence, takes refuge in the apartment of Richard Hannay (Robert Powell). Scudder has unearthed a plot to assassinate the Greek Prime Minister on a visit to London. Meanwhile the Prussian agents responsible for the previous killings locate Scudder. He escapes in search of Hannay, who is making his way to St Pancras for a trip to Scotland, but is stabbed. Dashing to his aid, Hannay is arrested for murder by the Chief Superintendent Lomas (Eric Porter). His detention is short-lived, and following a chain of events, including being dramatically snatched by the agents and going on the run, he makes the acquaintance of David Hamilton (Miles Anderson) and Alexandra Mackenzie (Karen Dotrice) and falls under suspicion for another murder. Eventually after fleeing from them and escaping once more from the agents he meets up with David and Alexandra again. After finall watch
