In his struggle to wrest the Mexican presidency from Victoriano Huerta, Venustiano Carranza lays siege to Querétaro, a town to the north of Mexico City. Querétaro is in chaos. People flee to the train station, hoping to escape Carranza’s squadrons. Among those thousands, Marta, her two daughters, and her son seek space on the train; however, their efforts are fruitless. The crowd separates them until Rosita’s voice catches Marta’s and Matilde’s attention. Rosita and Rubén manage to convince a doctor to allow them to travel in the medical car. The doctor opposes Marta’s and Matilde’s traveling with them, but Matilde declares that she has permission from General Malacara, an officer in charge.

Marta and her family tell her fellow passengers about the siege by Carranza’s army. The army took over the best houses, schools, and even the churches for military use. The cathedral was stripped of all valuables and turned into a hospital. Everyone agrees that greed is the worst enemy of the revolution—and the reason for its failure. The conversation is interrupted by the arrival of General Malacara, who, to Rosita’s surprise, comes with two women. General Malacara was flirting with Rosita; she feels that his attentions are serious.

The train travels all night with no problems, but almost everyone fears an attack by Carranza’s forces. Marta and her daughters prepare breakfast for the doctor; they believe that he is an important man, or at least one with money. The men continue their political discussion. The train suddenly stops near Irapuato, a town southwest of Mexico City. During an attempt to learn why the train stopped, Don Sinforoso insults a soldier, who threatens the old man with a rifle. Don Sinforoso’s friends take him away from the soldier.

Rosita flirts with the doctor, who, surprised by her friendliness, confronts her with the rumor that General Malacara courted her. Malacara assures Marta that his young women companions are distant relatives. Their conversation is interrupted by news about reasons for the delay: The northbound trains were derailed by a blockade, and hundreds of boilers are burning. General Malacara invites Marta and her daughters to an automobile ride around town. To his surprise, Marta declines the invitation, claiming that the doctor already invited the women.

The doctor does not own a car; instead, he owns a horse cart. The women display their displeasure. They climb up into the cart only when they are sure that General Malacara cannot see them. At Irapuato, people are evacuating the town because they fear that Pancho Villa lost the battle to Carranza. Rubén leaves to find Quiñones, a friend connected to Obregón, Carranza’s strongman. The women buy food with the doctor’s money, and they promise to pay him back when Rubén returns from looking for his friend. They also make him pay for boots for Rosita. When Matilde also wants boots, the doctor shows them his empty wallet. Marta takes that action as an insult, and she leaves the doctor behind, with a promise that they will pay him later.

They see General Malacara’s car approaching. Rosita again flirts with Malacara, denying any sentimental interest in the doctor. The women want Malacara to introduce them to Villa, who has a reputation for kindness. They plan to ask Villa for money, food, and passes to Juarez City. If Villa loses power, the women will have spent the money, while Rubén, aided by Quiñones, will be working on Carranza’s side. Malacara promises to arrange an interview with Villa, and he takes them to buy shoes. While they are in the store, Rubén arrives with good news: Rubén saw Quiñones, and Quiñones can help them. Rubén claims that he left his wallet behind, so Malacara also buys shoes for Rubén. On their way back to the train, Marta asks Malacara to take them to the governor’s personal car, claiming that the doctor flirted with Rosita.

Dissension among the supporters of Villa takes place. Men who swore loyalty to Villa decide to stay in Irapuato, so that the people from the town will think that they belong to the Carranza forces, and the Carranza men, when they come, will think that they are local citizens.

Marta and children arrive at the train station in search of Malacara. They are accompanied by Quiñones, who makes loud comments against Villa. A soldier overhears them and, by mistake, arrests Rubén, who is released when the women show proof that they are Villa followers; the proof is passes and Villa currency, presumably given to them by Villa. After the incident, they cannot find Malacara, but they find the doctor and again pretend friendship. Once in the hospital car, it is decided that Rubén should stay in the town in order to proceed with their plans. As the train rolls away from the town, military police suddenly climb into the wagons, as if escaping.