It's Derby day at Epsom Downs, and Lord Charles Sheridan is on hand to photograph the race with his new camera, while his wife, Kate, watches from the stands. It's a thrilling day for both Sheridans, until the race ends with a jockey's death. With her husband busy investigating, Kate retreats to the countryside to interview world-renowned actress Lillie Langtry for a magazine article. Plunging into her subject's less-than-illustrious past, Kate puzzles over the long-ago theft of the actress's jewels, and is not surprised when Charles's investigation heads in Langtry's direction. Now, sorting through rumors of bitter rivalries and torrid love affairs, the lord and his lady embark on a race for justice that stands to be a photo finish...