After his extraordinary adventures on the inaccessible island, Furio finds himself involved in a dark affair. On a drifting motorboat he finds the traces of a violent shooting and the body of a secret agent of the Peruvian police. By radio, he makes contact with a nearby torpedo boat, but the appeal is intercepted by the shady gang that has knocked out the Peruvian policeman and is now moving against Furio.
In the small village of Thaona, lost in the mountains of Mongolia, Ilona, the attractive daughter of a scientist, meets her fiancé Allan, who she met eight months earlier in San Francisco where the girl had finished her studies. After the introduction to her father, the two young people take a tour of the village curious to know its customs.
