As a young unmarried woman in 1950s Ireland, Philomena Lee is sent to a convent after becoming pregnant. She gives birth to a son, Anthony, and spends years working under harsh conditions while being allowed only limited contact with him. The nuns later arrange his adoption by an American family without giving Philomena a meaningful choice. Decades afterward, she tells journalist Martin Sixsmith about the child she never stopped searching for. Their investigation follows Anthony's life in the United States, where he becomes Michael Hess, a successful lawyer involved in Republican politics. The book brings together a mother's private grief, a son's hidden history and the institutions that separated them, while examining secrecy, faith, shame and the need to know where one belongs.