In Irkutsk, the detainees are waiting to be appalled. Instead, Ogareff arrives in the city and directs the attacks of the Tatars from inside: With the tsar seal, which he has taken from Strogoff, he turns out to be a secret messenger and gains the confidence of the governor. Nadia and the blinded Strogoff, constantly on the run from their pursuers, make a last desperate attempt to reach Irkutsk: in the middle of the enemy lines, they want to float on a raft up Angara to the threatened city.