Based on Cronin's famous novel, The Citadel follows doctor who fights to improve the conditions in Ireland's mines in the mid 1920s. Outraged by the inhumane conditions of the mines and the variety of illnesses that his patients suffer, Andrew takes up their cause. In his struggle to alleviate the horrible conditions in the mines, Andrew finds himself caught in the midst of a political power struggle. His influential colleagues manipulate him with empty promises and, over time, Andrew loses his way. His passion for medicine and altruism are lost to allure of ambition and the dream of wealth. Even more tragically, he loses Christina, the one great love of his life. Eventually Andrew realizes everything he has given up. He returns to his homeland and to the woman he loves, recommits himself to the cause he so believed in and finds true happiness by helping those who need him the most.