Jules Verne and the professor team travel to Irkutsk, in Siberia, but accept on the way to visit Artemius's old fan, the czar. Hearing he fears that his greatest treasure, 'the diamond', will be found and stolen by rebel Tatar leader Ivan Ogaraf's nomad men, they offer to accompany the czar's trusted envoy Michael Strogoff and inconspicuously evacuate the diamond. They survive traps set by the rebels, discover the actual, human nature of the 'treasure' and devise a deceptive way out before exposing the traitor at court.
—KGF Vissers