Irreverent Chicago racetrack publicist Jack Doyle, former advertising man and amateur boxer, accepts a new job as a thoroughbred jockey's agent. His client is a seventeen-year-old riding phenom from Ireland named Mickey Sheehan. Mickey and Jack prove to be an effective team until someone begins secretly doping the horses, affecting race results.

In his quest to identify the culprit, Doyle is aided by his old friend Moe Kellman, furrier-to-the-Mob; trainer Ralph Tenuta, himself the target of a blackmailer; and young veterinarian Ingrid McGuire, a talented horse communicator. The action moves from Chicago's Heartland Downs to New York's famed Saratoga Race Course, even stepping aboard Mob capo Fifi Bonadio's lavish yacht in Chicago's Belmont Harbor. Will Jack's persistent push for answers get him killed?