In South America during the early 1930s, bandits led by El Gavilan destroy a wildcat oil well owned by Jeff Dawson and his partner, Dutch Peterson. Their investment gone, Jeff and Dutch make their way, penniless, to the nearest city to find work and run into Paco Conway, a dear friend and former partner, who now owns the Conway Petroleum Company. Although Paco is eager to give them jobs, Jeff turns him down after learning that he has married Marina, an old flame of Jeff's. Instead, Jeff and Dutch accept a dangerous job delivering nitroglycerin across country for $800. Despite an attack by bandits, the partners successfully deliver the explosives, but are then cheated out of their pay by Jackson, the man who hired them. They consider returning to the United States, and try to hock their oil lease for passage money, but as the bandits have disrupted oil production in the area, the bank officer declares the lease worthless. While Dutch recuperates in the hospital from gunshot wounds suffered during the bandits' attack, Jeff reluctantly replaces Paco's inefficient foreman Henderson, but is uncomfortable around Marina, who pursues him aggressively. Claiming that she is "no good" and that he broke company with Paco several years before to get away from her, he turns down the foreman's quarters and moves to town to keep away from her. Her flirtations get bolder as his extra efforts to avoid her intensify, but he responds with disinterest and works hard for Paco. Jeff also distrusts another American woman, Sal Donnelly, who has been stranded in the country, but gets her money for boat passage. Later, however, Jeff finds that Sal, who has quietly fallen for him, has stayed and taken a job as a blackjack dealer. In the field, against Jeff's advice, Paco orders his men to set timed dynamite charges into a well in order to hasten drilling. Their work is interrupted by a shoot-out with bandits, who kill one of the oil workers. Later, after hearing El Gavilan order Paco to pay $50,000 or face the destruction of his eighteen wells, Jeff urges Paco to fight the bandits or be continuously at their mercy. However, Paco decides to pay them off, and Marina calls him a coward. Later, Jeff is told by an employee that the well that has been set with charges is now giving oil, and could be destroyed, if the explosives go off while it is gushing. As it gushes out with the oil, Jeff catches the cylinder holding the explosives and prevents it from exploding. Jeff is later treated for burns at the hospital, and Dutch scolds him for risking his life. As he is aware of Jeff's history with Marina, Dutch then warns him to leave the Conways. Later, Marina confronts Jeff and claims to love him, but unmoved, Jeff reminds her how she treated him when they were together. Having learned from Paco that Jeff is seeing Sal, Marina goes to the casino to try to scare her off, but Sal, who is unsure of Jeff's feelings for her, is confident that Jeff does not love Marina. Meanwhile, Paco is ashamed that he ran for cover while Jeff risked his life for the well. At a local cantina, Paco gets drunk and tells the crowd that his wife loves Jeff. When Jeff shows up to get him, Paco tells him that he plans to fight the bandits, then breaks free from Jeff and drives home alone. Still drunk, he tells Marina that Jeff is never coming back. In retaliation, Marina pushes Paco into an oil well, where the pumps crush him to death. When Jeff turns up later, Marina pretends that the drunken Paco fell in by accident. After the inspector takes away Paco's body, Marina asks Jeff to marry her, and when he refuses, she lets slip that she killed Paco to be with him, then threatens to name him as an accomplice in the murder. Jeff almost strangles her in a rage, but their argument is interrupted by El Gavilan and his men, who dynamite the wells. Marina is killed during the ensuing gunfight when the well in which Paco died suddenly explodes. Jeff runs out of ammunition, then kills El Gavilan in a hand-to-hand fight. Several days later, Jeff, Dutch and Sal pack up and leave for home together.