In her sixteenth year, Wing Toy learns how as an infant she was brought to Wong, a Chinese laundryman, by a former convict known as The Mole and that her father was Chinese and her mother American. Later, to give her a better home, Wong pledged her in marriage to Yen Low, a powerful and unscrupulous underworld figure, when she would come of age. Yen Low plans to divorce his American wife, White Lily, and marry Wing Toy. The intervention of reporter Bob Harris leads to the release of Wing Toy; Yen Low is killed by White Lily; and Wing Toy's engagement to the reporter becomes possible when it is revealed that she is the daughter of the district attorney.