Dan Sickles, congressman from New York, was married to the most beautiful woman in Washington but his other interests, including his mistresses, often kept him away from home. Feeling lonely and abandoned, his lonely young wife, Teresa, found comfort in the arms of Philip Barton Key. When Sickles learned of their affair, he armed himself and confronted Key on the street. Blinded by rage he shot and killed his wife’s lover. Was it premeditated murder or temporary insanity?