No, Michael, we don't belong together. I belong with Sean. It's the right thing to do. Sean needs me, and I know what to expect from a life with him.
Young Irish immigrant Kathryn O'Meara's memories of her past in Ireland are filled with tragedy. Yet she can't bring herself to set a date to marry Sean Gallagher, the brave Irishman and childhood friend who rescued her from a heartbreaking betrayal and brought her and her sister Peggy to America for a new beginning.
When a close friend suffers a tragic loss, it brings Kathryn together with a kind, young Bostonian doctor who has come to set up practice in the working-class neighborhood where Kathryn lives: a neighborhood of laborers who work in the iron and textile mills in the Massachusetts of 1876. An immediate attraction develops between Kathryn and the doctor, who are from very different worlds. Overwhelmed by her attraction to the young doctor, who despite his wealth also carries memories of a heartbreaking loss, Kathryn must fight their growing closeness or risk breaking Sean's heart. She owes Sean so much, and Sean fights tirelessly every day for a better future for them and for all the workers and their families in the mills.
Then the unimaginable happens, and everything is changed by a single event. Shadows of Kathryn's traumatic past reenter her life, and she must fight for justice and her very survival while trying to decide between one lonely man who loves her and another man whose heart has been shattered forever.