A revolution threatens to detach the Siberian provinces from the influence of Russia. All forms of communication between Moscow and the rebellious regions have been interrupted. The tsar's brother, who is in Irkutsk, five and a half thousand kilometers away, is in immediate danger from the traitor Ivan Ogarev and must be urgently notified.

Then the capable and intelligent captain Mikhail Strogoff undertakes a great mission: to deliver the tsar's letter to his brother. The dramatic incidents that mark the journey of the tsar's courier succeed one another, and amidst the terrible adventures and mortal dangers, a great love is born.