Dr. Quest, Race, and Jonny are in Calcutta investigating the use of nerve gas on a number of mountain sheep herders. They are introduced to Hadji when he foils an assassination attempt on Dr. Quest. The four head off in search of the assassins and the men behind the use of nerve gas. With the help of a Indian merchant named Pasha Peddler, they discover a secret weapons factory inside a mountain. Dr. Quest, however, is captured and taken within the mountain. He is eventually rescued by Race. After they leave, Dr. Quest uses his sonic amplifier to create an avalanche which buries the assassins and destroys the weapons factory.