At eight months pregnant, Mun-hi tries to kill herself but she is saved by the police. She goes to Mary's Home. Mary's Home is where unwed mothers live with nuns to repent their immoderate lives and try to find new lives. Earlier, Mun-hi, a college student, meets Se-hun who is studying for the bar exam. Mun-hi supports him and becomes pregnant with his child but Se-hun marries Eun-kyung instead. Mun-hi takes her child from Mary's Home and intentionally leases out a room in Se-hun's house. Mun-hi's relentless revenge torments Se-hun. However, suffering from valvular disease of the heart, Mun-hi dies leaving her child to Se-hun and Eun-kyung.