Richard Hannay finds a man named Scudder murdered in his flat. Scudder had uncovered a spy ring and was hiding from them. Hannay takes Scudder's notebook and goes on the run from both the murderers and the police. He travels through Scotland pursued by them. Hannay meets some people who help him and connect him with Sir Walter Bullivant at the Foreign Office, who believes Hannay's story. Together they work to capture the spies who they discover plan to leave the country from a spot on the coast with 39 steps down to the sea.