Epic tale about the lives of crew members aboard a US gunboat, patrolling China's Yangtze River in 1926, that eventually gets caught up in the middle of that country's Civil War.
In 1926, as strong feelings of nationalism are sweeping through China and the followers of Chiang Kai-shek, as well as the war lords and communists, are demanding that all foreigners leave Chinese soil, the U. S. gunboat San Pablo is patroling the Yangtze River. The newest member of the crew, who call themselves "sand pebbles," is Jake Holman, a machinist with 8 years previous Navy duty. Although Jake's independent nature is regarded with suspicion by most of the men, he wins the friendship of Frenchy, a sailor in love with an English-educated Chinese girl, Maily, who has been sold into enforced prostitution. When Chiang Kai-shek moves against the feudal war lords, the United States decides to treat the upheaval as a civil war, and the San Pablo is ordered to confine its function to protection of American civilians in the area. Included among them are Mr. Jameson, a missionary, and Shirley Eckert, a schoolteacher whom Jake met earlier. In an attempt to draw the San Pablo 's fire, the Chinese capture Jake's coolie assistant, Po-han, and torture him by slashing his chest with a knife. Unable to bear his friend's agonized screams, Jake grabs a gun and puts a bullet into Po-han's head. Later, Frenchy buys Maily's freedom and takes her as his common-law wife because they cannot legally marry. While the San Pablo is forced to remain in a state of siege, Frenchy swims ashore each night to visit his pregnant wife. But the icy waters precipitate pneumonia and he dies in Maily's room. When Jake visits the bereaved woman, the Chinese beat him and put Maily to death. They then brand Jake as the murderer and demand that the San Pablo hand him over for trial. The crew agrees that Jake should be tried, and when Captain Collins refuses the demand and orders the crew to fire on the Chinese the men nearly mutiny. The captain takes advantage of the rising tide and moves his ship into deep water. When word arrives that full-scale fighting has led to the landing of U. S. Marines in Shanghai, Captain Collins decides to give his humiliated ship and disgraced crew a chance for glory by heading for Jameson's mission and a rescue attempt. After a bloody fight, the San Pablo breaks through a Chinese blockade and reaches the mission. But Jameson and Shirley declare themselves stateless and rebuke the captain for interfering in China's affairs. Jake wants to desert, but neutrality is no longer possible. Nationalist troops, incensed by the San Pablo 's defiance of the blockade, storm the mission and kill both Jameson and Collins. Pushed into making a last stand, Jake orders the other crew members to take Shirley to safety while he covers their getaway. But he is killed by a Chinese bullet. As he dies, he cries "I was home. ... What the hell happened?"
