Drama based on John Buchan's classic novel, set in the lead-up to the First World War. When an undercover British spy is killed in his flat, a man finds himself accused of murder and caught up in a deadly conspiracy, which threatens not only his life, but the safety of the nation. Pursued by spies and the police, he reluctantly joins forces with a feisty suffragette as he attempts to uncover the truth and save Great Britain from invasion.