A Frenchman imprisoned during the Napoleonic wars escapes to prove his innocence.

In 1813, during the Napoleonic Wars, a small party of French soldiers is captured by the English and taken to a fortress in Edinburgh, Scotland. Among the group of ordinary soldiers is Anatole de Keroual, formerly the Viscount of St. Ives, who was demoted from his officer status when a prisoner in his charge, a fellow aristocrat, escaped. Determined to escape from their captors, the men dig a tunnel during the night. In the meantime, Anatole contacts his elderly uncle, the Count St. Ives, who has settled in England, asking him to visit the prison. Anatole has one visitor, Flora Gilchrist, a young woman whom he met earlier in Switzerland. In an attempt to aid Anatole, with whom she is in love, Flora asks Major Edward Chevenish to parole him. Chevenish responds that only officers can be paroled and then proposes marriage to Flora, who rejects him. One night, Anatole and another soldier quarrel. Anatole wins the subsequent duel and spares the soldier's life, but when the other man tries to stab him in the back, Anatole is forced to kill him. The next visiting day, Daniel Romaine, an emissary from Anatole's uncle, delivers a large sum of money to Anatole, who admits that he will use it to facilitate his escape. Unknown to Anatole, however, Romaine is in league with Allan St. Ives, Anatole's cousin, who wishes to eliminate his rival for his uncle's fortune. Before he leaves the prison, Romaine tells Chevenish of Anatole's escape plans. While Chevenish questions Clausel, one of the soldiers, who eventually accuses Anatole of murdering the other soldier in cold blood, the others take advantage of a storm to set an explosion and escape. After arranging a rendezvous in London, Anatole hurries to Flora's home to say goodbye. Knowing of Anatole's relationship with Flora, Chevenish suspects that he will find him there and tries to search the house, but her aunt, Annie Gilchrist, prevents him and then arranges for Flora and Anatole to travel disguised as shepherds. Meanwhile, Allan and Romaine hear that an escaping prisoner was killed and tell the count that it was Anatole. The count makes a new will, naming Allan as his heir. After several close calls, Anatole and Flora arrive at the rendezvous point in London. Unaware that he has been betrayed by Romaine, Anatole visits his office and overhears Allan and Romaine plot to poison the count. Anatole hurries to the count's home and prevents the murder, but Allan summons Chevenish, who arrests Anatole for the murder of the other soldier. When Flora learns what has happened, she wants to rush to his aid, but is unable to do so because her money has been stolen. She then contacts the count and, along with him and Sergeant Carnac, who vows to testify that Anatole acted in self-defense, arrives just in time to save Anatole's life.