Captain Hugh North of G-2 is on a river boat heading towards Shanghai during a time when there is much fighting and turbulence surrounding that city. On the trip a young Englishman named Trenchard is murdered. North is joined on the boat by his friend from British military intelligence, Bruce Kilgour. North learns that Trenchard was a British agent trying to get information on an arms shipment being sent to General Wang, a warlord with ties to French and Italian interests. Wang is now threatening Shanghai which is defended by General Yuan who is backed by England and the United States. A third army planning to attack Shanghai is led by an American soldier of fortune named Sam Steel. He is an employee of a warlord named Wu.After North arrives in Shanghai, he meets with American Admiral Clegg who explains the task awaiting the military intelligence captain. North's mission is to locate the arms shipment before either General Wang or Sam Steel can seize it. Hopefully North can find the shipment in time to prevent a disaster for the American and English residents of Shanghai.Almost every country with a political or economic interest in Shanghai has a representative engaged in the struggle to acquire the arms shipment. As usual North finds that the lines between friend and foe often seem blurred.