Set in the 18th century, the film follows the continuing exploits of cartographer Jonathan Green as he undertakes a scientific and supernatural journey that leads him from England to China. Along the way, he discovers Russian Tzar Peter I in prison in the Tower of London under the watch of pugilistic Warden Hook, as his wife Lady Emma discovers the Chinese Princess posing as Jonathan’s assistant Chen-Lan. As Tzar Peter escapes and joins a Russian ship, he tails Lady Emma as she uncovers an imposter robbing the Chinese people while posing as Princess Chen-Lan.