Against the wishes of his mother, Marty Kruger becomes a jockey, like his father, and soon gains an outstanding reputation. He joins the Tupper stables and, despite the tyranny of trainer Hippo Devlin, finds happiness in his work and falls in love with Katie Kelly, a lunchroom waitress. They are engaged at the time Marty is laid up by an accident, and as he returns to the track overweight, Devlin forces him to reduce to the point of endangering his health. "Silk" Conlon, representing betting interests, wants the Tupper entry to lose the race and tries to bribe Marty into eating a square meal; but he refuses for fear of disgrace, and though he wins the race, he faints from weakness. Tupper thrashes the trainer and fires him, and when Marty and Katie are married, Marty is made Devlin's successor.