Set in China on the eve of revolution, the book tells the story of an old U.S. Navy gunboat, the San Pablo, and her dedicated crew of "Sand Pebbles" on patrol in the far reaches of the Yangtze River to show the flag and protect American missionaries and businessmen from bandits. The plot revolves around a newcomer to the boat, machinist's mate Jake Holman, a maverick and loner who dramatically alters the lives of the crew and the people they have come to save. A faithful engine-room coolie and a pretty young missionary help Holman gain an appreciation of China and its people and discover a world of humanity and promise he has never known. It is a story of old loyalties versus new values, of violence and tenderness, tragedy and humor, and it engages the reader from the first line to the last.