When Tai Choi leaves her home in the Zhejiang province of China, she believes she'll be visiting her grandmother. But in truth, despite her mother's opposition, her father has sold her to pay his gambling debts. Alone and afraid, Tai Choi is put on a ship headed for San Francisco, known among the Chinese as Gold Mountain. When she arrives, she is forced to go by the new name listed on her paper documents: Tien Fu Wu.

Her new life as a servant at a gambling den is hard. She is told to stay hidden, to stay silent, and to perform an endless list of chores, or else she will be punished. Tien Fu thinks her life couldn't get any worse, until she is sold again to an abusive shopkeeper and tasked to care for a young boy. If she is to survive, Tien Fu must persevere, and learn who to trust.

When Dolly Cameron arrives in San Francisco to teach sewing at a mission home for orphaned Asian girls, she meets Tien Fu, who is willful, defiant, and unwilling to trust anyone. Dolly quickly learns that all the girls at the home were freed from lives of servitude and maltreatment. Dolly immediately joins the group of women dedicated to saving more of these "paper daughters" because some in authority have turned a blind eye to the situation.

Despite many challenges, Dolly and Tien Fu forge a powerful friendship as they mentor and help those in the mission home and work to win the freedom of thousands of immigrant women and girls.