Rui is determined to persuade Lucena to replace his horse-breeding operation with sugarcane cultivation and to jointly set up an ethanol plant. To this end, he forces a marriage between his son, Marcelo, and Lucena’s daughter, Diana. The "Black Beetle" intervenes in this plot. Lima, who, like Marcelo, seeks a way to defeat his rival, the car, pursues his goal by doing what he knows best: taming Cleide, the "other woman" in Marcelo's life. The Black Beetle acts as the connecting link, creating an atmosphere of fear and curiosity for both parties and driving the story toward an unexpected conclusion.