England, 1913. Ainsley Fotheringill travels to Russia to take up a new position as a translator of fiction. Travelling on the same train is the Countess Alexandra Vladinoff, who is on her way to be presented to the Czar on the eve of her wedding to a military Colonel. Meanwhile, Fotheringill finds himself in trouble with the Russian police for a translation deemed critical of the state. He is ordered to leave the country within two months. When he is offered by an English friend a chance to remain in Russia as a spy infiltrating the revolutionary Bolshevik movement, he accepts the position after some thought. He is given the identity of Peter Uranov, and told that in the event of capture, he cannot expect any assistance from his government.
Peter becomes involved in a Bolshevik cell led by a bookseller Axelstein. When Peter is implicated in a failed attempt to assassinate the Countess's father, he is sent to Siberia, just as Russia is preparing for entry into the War. The Countess's husband is killed in the conflict.
1917. As the revolution takes hold, Peter and his associates are returned from Siberia. Axelstein is appointed Commissar of Kalinsk, and selects Peter as his assistant. The Bolsheviks march on the opulent palace of the Countess, and she is taken captive while the palace's treasures are destroyed. When Axelstein arrives, he realises that the mood of the crowd is ugly, and that the Countess must be moved if she is not to face a firing squad. He orders Peter to take her to Petrograd. Escaping angry crowds, Peter and Alexandra leave with two guards, arriving the next morning at the train station, where they will wait for a train to Petrograd. Peter dismisses the two guards, and they settle down to wait, only to discover that no trains are running. Meanwhile, the two guards decide to return. There is a struggle and Alexandra shoots one of the guards, while the other takes off.
Leaving the station, Peter and Alexandra come across a crowd, and learn that they are fleeing a White advance. They make for the Cossack line, where Peter says farewell, telling Alexandra to present herself to the Cossack troops and demand to see the commanding officer, who turns out to be a friend; she gratefully accepts an invitation to dinner, and revels in reacquainting herself with luxury. Peter, meanwhile, falls in with a band of Red soldiers.
The White stronghold is attacked by the Reds, and the Countess is captured, but Peter manages to obtain access to the prison, and releases her, and they flee into the woods, where they manage to hide out until their pursuers have called off the hunt. Now very much in love, Peter and Alexandra disguise themselves as peasants and manage to board a train heading south. Arriving at Kazan, they present themselves as brother and sister, but Alexandra is recognised. However, when her denial is corroborated by a former gardener on her estate, a young officer, Poushkoff, takes pity on them and allows them to pass.
Accompanied by Poushkoff, they board a train. Despite being aware of their true identities, Poushkoff, a sensitive man, befriends them. Arriving at their destination, Poushkoff kills himself, and in the confusion Peter and Alexandra escape. They make their way to a small boat, but Alexandra has now fallen ill. The boat takes them to Astrakhan, where Peter goes on land to fetch a doctor, but is captured by soldiers. Meanwhile, a Red Cross doctors board the boat and attend to Alexandra. Peter is sent to a firing squad, but manages to escape and boards a Red Cross train, where he promptly collapses. Treated on the train by an English doctor, he tells his story and learns that Alexandra is on another train. Peter boards Alexandra's train just as it is departing, and the two lovers are reunited.
