Based on a true story, Mrs. Soffel is set in Pittsburgh near the dawn of the 20th century. Peter Soffel (Edward Herrmann) is the warden of a top security prison, and his wife Kate (Diane Keaton) often comes by to read the Bible aloud to the inmates, despite her fragile health. While making her rounds, she makes the acquaintance of the Biddle Brothers, Ed (Mel Gibson) and Jack (Matthew Modine), who are sentenced to death for murder and robbery. Ed has become something of a celebrity thanks to his letter-writing campaign, in which he appeals in the letter-to-the-editor columns of the popular press to stay the execution of his brother and himself. His good looks, intelligence, and charm make a strong impression on Kate, whose marriage offers her little excitement. In time, Kate finds herself falling in love with Ed, and she discovers that she's unexpectedly receptive to his suggestion that she help him escape.