Sid Holly, having received a serious injury, is forced to change his career as a jockey to work as a private detective. On behalf of the Jockey Club, he begins an investigation into the mysterious losses and deaths of favorite horses from the stable of George Caspar, a trainer with an impeccable reputation. From the first steps, Sid feels opposition and pressure. Too significant figures are involved in the scandal, too much money is thrown under the hooves of racehorses. Holly is faced with a choice: continue the investigation and risk her life, or abandon it, but forever lose self-respect.