When Red and Tom arrive at his cabin on the range, Red urges Tom to make himself at home and explains that his lessons will begin the following morning. Red also introduces him to Meo, a Mexican who works as Red's cook. Meo had been a wild bronco rider until he became injured during a ride. The next day, Tom falls off his bronco after only four jumps, and Red begins his coaching with Meo's assistance. Tom's riding abilities quickly improve with his daily lessons. Red and Meo strive to prepare him to ride in the Aztec show scheduled for the following month. In addition to Red's training of Tom in the saddle, he also provides him with other advice. He urges him not to trust anyone with his saddle and his gear and to vent his frustrations through the wild bronco. Finally, he informs Tom that he must intentionally lose the final round at the competition, as he plans to bet against him as part of his larger moneymaking scheme. At first Tom refuses to sacrifice a potentially stellar performance for Red's selfish ends, but Red, yelling at him, forces him to comply.
Traveling to Aztec for the competition, Red and Tom contemplate the upcoming event, which will be difficult as a single failed round eliminates the rider. Tom, determined to stay in the competition, performs well on the first day and similarly on the second. The crowd has begun to demonstrably support Tom, which delights him. On the third day, Red reminds Tom that he must lose in the final round, casting a threatening look upon the boy in order to intimidate him. When Tom intentionally loses the last round, he feels low and ashamed. While Red publicly sympathizes with Tom, he privately celebrates with money he has won by betting against him. As the competition draws to a close, Red tricks a man into betting with him again in a further informal competition, in which Tom further pleases the crowd. Taking out his frustration on the bronco, much as Red has advised him to do, Tom eventually kills the bronco with the force of his jolts and spurs. The man who has bet against Tom realizes he has been part of a setup, and demands that Tom never return to the Aztec competition in the years to come.
Laughing and boasting of his trick against the Aztec crowd, Red exults in his victory, while Tom disappointedly mulls over his loss in the final round and becomes ill at the notion of the bronco's death. Having stopped for drinks at Blanco, Tom drowns his sorrow and frustration in drink. Traveling toward Red's cabin, Tom becomes unable even to remain awake atop his horse.
This new fourth part of the novel, entitled "The Arena," marks yet another phase in Tom's life. Tom will train to become a bronco rider and will ride for the majority of his life. Despite his skill at this profession, however, he still remains largely powerless in determining his own fate. Just as teachers and bosses had previously exerted their positions of authority over him, Red similarly demands that he obey his every word. In addition, once again Tom must dedicate his own abilities and efforts to the profit of others. Just as the school had sold his handmade bridle to the Bayfield store for a hefty sum, Red uses Tom's skills to earn betters' money. Understandably, Tom's lack of control and agency results in his frustration and misery.
In this part of the novel, we first gain an in-depth perspective on Red's character. Underhanded, greedy, and selfish, Red manipulates Tom by forcing him to ride in ways that he would not normally ride, for the sole purpose of winning gambles. Aware that Tom needs him, to instruct him, provide him with horses to ride, and to feed and house him, Red takes advantage of his position to exploit the boy.
When Tom experiences the disillusionment of the competition at Aztec, he begins to bitterly resent Red and his selfish ends. These feelings will recur throughout his time with Red. In the passage describing their journey from Aztec back to Red's home, Borland draws a particularly vivid picture of their distinct states of mind. While Tom sits low in the saddle, dejected, ill, and ashamed, Red "exults" in his victory. Tom resents this celebratory behavior, for his definition of victory differs from Red's. Tom will never feel as though he has won a competition unless he has truly won, while Red defines a victory as a won gamble. In Chapter 24, Borland writes of Tom, "He looked at Red, heard his braggart voice, his jeering laugh, and remembered the way he had gouged with his spurs, punishing not the horse but something else, something that Red Dillon represented. He had punished it, gouged and fought and mastered it, rode the horse to death. And Red Dillon's voice and grating laughter were still right bedside him."
The death of the horse Tom has ridden saddens him deeply, and he feels remorseful that he has caused it with his brutal riding, as well as queasy over the concept of its death. This reaction indicates that, at this point in his riding career, he remains somewhat sensitive to the horses' place in the world and that of animals in general. His sick feelings speak to his sense that the act of killing has been fundamentally wrong. Later on in the novel, these instincts and feelings will fade as his behavior becomes increasingly callous and brutal. Tom's treatment of the horses also strikes us as somewhat ironic. While his own will becomes subdued, through Red's ranting and through the overall abuse he has endured, he learns in turn to subdue the will of the horses—to "break their spirit" and at times to kill them.