Former advertising man, amateur boxer, and track publicist Jack Doyle undertakes a new job in the world of thoroughbred horse racing as a jockey's agent. His client is a seventeen-year-old feminine riding phenom from Ireland named Mickey Sheehan, who has decided to try her luck in the States. They prove to be an effective team until misadventure occurs as the result of someone secretly administering dangerously illegal medications to horses. In his quest to identify the culprit, the shrewd, irreverent, and always opinionated 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 greatly talented horse communicator. Jack and Moe become co-owners of a talented, bargain-priced colt named Plotkin, who provides several thrills, not all of them welcome. Mickey's sibling rivalry with her occasionally race-manipulating brother Kieran, one of Ireland's top jockeys, comes to a climax with Mickey aboard Plotkin in the million dollar Heartland Downs Futurity. The primary setting is the Chicago area racetrack Heartland Downs. Other major scenes take place at New York's famed Saratoga Race Course and aboard Mob chieftain Fifi Bonadio's lavish yacht in Chicago's Belmont Harbor. Doyle is sometimes mistaken but invariably persistent in his search for answers. The challenges he faces in attempting to halt the horse drugging and the threat to Tenuta's life are the most daunting of his colorful career as an amateur investigator in the world of American racing.