Penelope MacLaughlin marries a miller and gradually discovers he is not as she imagined. Nonetheless she remains determined to make the best of life at the lonely mill up the Gunn Brook as she struggles to build a home around her husband's eccentricities. His increasing absence leaves Penelope to run the mill herself, providing her with a living but also destroying the people she loves most. Penelope struggles with loss and isolation, and suffers the gradual erosion of her sense of self. A series of betrayals leaves her with nothing but the mill and her determination to save her grandchildren from their disturbed father.