It's Derby day at Epsom Downs, and the Sheridans are on the scene. While Lord Charles sets up his camera to photograph the race for the Jockey Club, Kate absorbs the atmosphere for her new novel. Watching the Derby from a box shared with Jennie Jerome Churchill and world-renowned actress/mistress/horse-owner Lillie Langtry, Kate senses something strange about the outcome. And that evening's news bears out her suspicions.
It seems that while some gamblers lost their shirts on the race, one unfortunate jockey lost his life. Hard on the heels of that shock comes a request from the Jockey Club at Newmarket that Charles investigate the theft of Lillie Langtry's jewels from their vault. The case pulls Kate and Charles into Miss Langtry's fast, frantic social circle as they probe into her secret life, getting caught in a dangerous web of intrigue. There are no safe bets as bitter rivalries and past love affairs cast suspicion in all directions. Now, as the lord and his lady run neck and neck with thieves and murderers, the race for justice stands to be a photo finish.