1950's America. Muriel, newly married and newly orphaned, works as a waitress in a San Diego diner. As she pours coffee and empties ashtrays, she eavesdrops on her customers, the ex-jockeys and trainers of the Del Mar racetrack. When she begins, secretly, to bet on the horses and, shockingly, to win, she feels strangely unready to share her good luck and its origins with her husband Lee.