Engineer Jake Holman arrives aboard the gunboat U.S.S. San Pablo, Delegated to patrol That a tributary of the Yangtze at the Centre of exploited and revolution-torn 1926 China. His iconoclasm and cynical nature soon clash with the"rice-bowl" system which runs the boat and also the uneasy symbiosis between Chinese and foreigner in the lake. Hostility to the presence of the gunboat reaches a climax when the boat must crash through a river-boom and rescue missionaries upriver at China Light Mission.