In the early part of the twentieth century, Wong Low Get, the hatchet man for the Lem Sing Tong in San Francisco, is responsible for dispatching justice with the stroke of his hatchet. When a Tong war erupts, he is ordered to kill his best friend, Sun Yat Ming. Though Wong tries to refuse, he knows his duty to the Tong and goes to visit his old friend. Before he dies, Sun makes his will in favor of Wong, giving him guardianship over his six-year-old daughter Toya and pledging her in marriage to Wong when she comes of legal age. Wong rears Toya in both traditional Chinese and modern American ways. When she is a grown woman, he asks her to marry him, rather than forcing her to honor her father's will. She agrees, out of respect for her father's wishes, and because Wong has been so kind to her. Soon after their marriage, another Tong war breaks out. Wong, now a successful businessman, calls for negotiation, but, as a precaution, Nog Hong Fah, the head of the Lem Sing Tong, hires some young Chinese gangsters from New York to act as bodyguards. One of Wong's bodyguards is Harry En Hai, a young man close to Toya's age who she had briefly met at a dance hall before her marriage to Wong. While Wong is in Sacramento killing "Big Jim" Malone, the white gangster who started the war, Harry and Toya go dancing together and fall in love. When Wong returns, he finds them in each other's arms and plans to kill Harry. Because he had vowed to Sun always to make Toya happy and she says that Harry will make her happy, Wong goes against tradition and lets them go after making Harry promise before Buddha to keep the same vow. Nog, who has observed Wong's actions, reports them to the Tong, and Wong is ostracized by his fellow Chinese. Soon his business fails, and he is forced to become a field worker. Some years later, Wah Li, Toya's old nurse, brings Wong a letter from China from Toya. In the letter, Toya says that she has been enduring a living death and begs his forgiveness, and also says that she has always loved him. After working his way to China shoveling coal on a steamship, Wong learns the location of the opium den where she is held prisoner after Harry sold her to the owner, Madame Si-Si, to pay his debts. When Wong and Toya are reunited, he is challenged for her by Madame Si-Si, but he tells her that ancient Chinese law commands that a wife belongs to her husband. When he reveals that he is a hatchet man, she does not believe him. Wong then throws one of his weapons at a dragon painting on the wall to demonstrate his hereditary skill, and does not realize that he has inadvertently hit Harry, who is sitting behind the wall. Free from their past, Toya and Wong leave to resume their marriage. When Madame Si-Si goes to berate Harry for the loss of Toya, he blankly nods his head, then falls dead, as the hatchet, which her servant has been removing from the wall, is revealed to have lethally struck Harry in the skull.