On September 10, 1946, Mother Teresa, a nun in the Catholic order, was riding on a train when she received what she took as a message from God telling her to assist the poorest of the poor, and to live among them. Committing to this new purpose brought her initially in conflict with the Catholic Church and the Government of India. Undaunted by the obstacles and challenges of her new calling, she rose to become viewed by many as the greatest humanitarian of modern time. Letters from Mother Teresa tells the story of how this tiny figure of a woman changed hearts, lives and inspired millions. Though she herself grew to feel an isolation and an abandonment by God, she said she saw God in every human being. The movie explores the life of Mother Teresa (Juliet Stevenson) through letters she wrote to her longtime friend and spiritual advisor, Father Celeste van Exem (Max von Sydow) over a nearly fifty-year period.