The Thirty-Nine Steps

Richard Hannay finds himself in London while WWI is brewing. After befriending an American spy, he learns of an assassination plot that could send Britain to war. When the American is found murdered, Hannay becomes the prime suspect. The British police and the German spies that killed the American give chase. Carrying a black book filled with German secrets, Hannay must unravel the mysteries of his friend's murder and clear his name before it's too late.