Margaret Treacy, a poor farmgirl in Ireland, comes to New York, hoping to find a position as a maid in a fashionable house. And she does. But it all falls apart when she's dismissed without an explanation and set adrift. A maid for a never-in-fashion new-money family, a factory worker, and a nun. She leaves the order when she learns that her first mistress couldn't bear her presence. Because it prevented her from fulfilling her obligation to "love" a man and have his children.
Margaret and that woman, Elinor, arrange to be together, however platonically, till Elinor's world is shattered when she and her daughter are forcibly taken to London. And it becomes Margaret's obsession to get her back. And to save her.