The Kitchen God's Wife explores the heritage of Pearl, a Chinese-American woman who has never really felt in touch with her family. When she is called home to San Francisco for an engagement party and a funeral, her aunt gives her an ultimatum, and then does the same with Pearl's mother Winnie, insisting that she tell Pearl about her troubled past. As Winnie reveals her life story, the two women become more deeply connected, reinforcing the novel's themes of cultural identity, family, and understanding.
The novel opens with the narrative voice of Pearl Louie Brandt, The American-born daughter of a Chinese mother and a Chinese-American father, living in San Jose, California. Pearl's mother, Winnie Louie, has called her to request that she and her family come to San Francisco, to attend the engagement party of Bao-Bao, her cousin. Later, Pearl receives another call from her mother telling her that her elderly Auntie Du has died, with her funeral being arranged for the day following Bao-Bao's party.
Upon her arrival in San Francisco, her Auntie Helen makes a demand: she insists that Pearl must tell Winnie that she has multiple sclerosis, something which everyone else in the family knows; Helen claims that she is suffering from a malignant brain tumor and does not want to die knowing that Winnie is unaware of her daughter's illness. Helen adds that if Pearl will not tell the truth, she will do it herself. Afterwards, Helen has a similar conversation with Winnie, telling her that she must reveal the truth of her past to Pearl.
At this point the novel switches to the narrative voice of Winnie Louie, telling the story of her past. Before reaching the United States, Winnie experience a life of turmoil and suffering: She was abandoned by her mother, a lesser wife of her father, as a young child, and did not fully understand her mother's mysterious disappearance. She was forced to live with her uncle and his two wives, never feeling as loved as her uncle's daughter, Peanut. Nevertheless, when the time came, Winnie's aunts arranged a traditional marriage for her, and her father provided a large dowry, since he was an educated and well-established man.
The marriage to Wen Fu, who first courted Peanut but transferred his attentions to Winnie when he learned of her father's wealth, turned out to be a disaster. Winnie suffered physical and mental abuse at the hands of her husband, losing many children along the way. Throughout her marriage, Winnie does many things behind the scenes that her husband takes credit for, and she likens her situation to a Chinese fable about a man who was horrible to his wife no matter how much she did for him, and yet still became known as "the Kitchen God".
It was during the war that Winnie met Jimmy Louie, Pearl's father; He was a good husband, a good father, and a minister in the Chinese Baptist Church, but he died when Pearl was a teenager, a time when Pearl became very angry. Winnie explains to Pearl that she met Jimmy Louie in China, at an American military dance. The two fell in love and he began to help escape her abusive marriage. In order to gain a divorce, the paper has to be signed by two witnesses and Grand Auntie Du and Helen agreed to sign. Wen-Fu had previously ripped up the papers from her first attempt, and Winnie went to him again to get the papers signed. At this second meeting Wen Fu raped her. Winnie explains that she has always tried to love Pearl more because she thought she might have been Wen-Fu's daughter.
After Winnie tells her story, Pearl reveals the secret of her disease. By the time the wedding of Bao-Bao comes around, mother and daughter have come to know each other better. Winnie goes into a local shop finds an altar with an unnamed goddess. The shopkeeper gives it to her for half price because it is considered bad luck. Winnie names it "Lady Sorrowfree" the wife of the Kitchen god, who has endured all, received no credit for the work she has done, and is still strong. At the end of the novel, Helen reveals that she is planning a trip to China, with Pearl, and Winnie.