In Toronto, Canada, a Canadian Chinese woman cooks a meal of baozi for her and her husband. One of her buns comes alive, much to her shock. She raises the dumpling as a child, feeding it and caring for the bun, who enjoys the time he spends with her. Eventually the child sees other children playing and wishes to join them, but the overprotective mother refuses to allow him to do so, much to his ire. As her son grows, he desires increasing amounts of independence, which creates tension between the two of them that gradually alienates them from each other. When the steamed bun introduces the woman to his new fiancée, with whom he will leave home, the woman protests. She tries to stop the steamed bun from leaving, but he pulls free.
In a fit of anger, the mother eats the steamed bun, after which she cries over what she has done.
Later, the mother lies in bed, and her real-life son enters the room, revealing that the whole sequence was an allegorical dream. The woman's husband urges their son to talk to his mother, but she rebuffs him. As he and his mother sit on the edge of her bed, he offers her the same treat he once refused on the bus, which they share in an emotional moment. Later, after reconciling, the son and his fiancée join his mother in making buns, as his father looks on with approval.