The caravan is led by Byambyn, who has brought his family along in order to visit relatives along the Selenga river. Unfortunately this includes his prankster cousins who sneak spiders into Passepartout's bedclothes.
En route the caravan finds a woman named Veruschka wandering the land alone. She is an escaped convict being pursued by a troop of Cossacks, and claims she was detained for her part in a revolution to improve life for the peasants of Russia. Upon arriving in Urga, the caravan must decide weather to smuggle Veruschka into the city and risk imprisonment themselves or abandon her outside.