In 1912 American pilot Lee Arnold is smuggling guns into Mexico and selling them for gold to Captain Ramirez and the insurrectionists. While waiting for his plane to be repaired after one such mission, Arnold witnesses a brutal attack by Ramirez and his men on a village known for its allegiance to Pancho Villa and the revolutionary government. When the town is retaken by Villa's sadistic aide, Fierro, Arnold is sentenced to execution for having helped the enemy; but he is spared at the last minute by agreeing to serve as Villa's one-man air force. As Arnold bombards Ramirez' men with homemade grenades, Villa and his followers capture first an enemy troop train and then an entire town. Villa's success infuriates revolutionary commander General Huerta, who had ordered Villa not to attack the town. To facilitate taking over the government from President Madero, Huerta sends Villa on a suicide mission by ordering him to take the city of Conejos. Although many of Villa's men die in battle, Arnold secures victory by bombarding the enemy from the air and crashing his plane into barbed wire holding back Villa's men. After Villa has killed Ramirez and forced the officials of the captured city to pay his troops, he is arrested by Huerta for allegedly disobeying orders. Arnold escapes by bribing his way across the border into El Paso. Sometime later, Villa and his lieutenants find Arnold in Texas. Having escaped from jail, they again need Arnold's help to overthrow Huerta, now installed as dictator after having assassinated Madero. Arnold finally agrees to assist in raising another army to march on Mexico City, this time against Emiliano Zapata.