Beck (Dwayne Johnson
) is a professional bagman who chooses not to use guns in his work due to a previous bad experience. His boss Walker (William Lucking
) hires him to get Walker's son, Travis (Seann William Scott
), from the Amazon jungle. Beck wants out of the business, and Walker agrees to make this his last job before Beck retires and opens his own restaurant. He heads down to the small South American mining town of El Dorado (nicknamed "Helldorado") to find Travis and retrieve him. A man named Hatcher (Christopher Walken
) runs the town, and the people are broke due to his monopoly on mining supplies.
Beck quickly captures Travis, but Travis escapes with the help of Hatcher. Travis is looking for an ancient golden artifact known as the Gato that, if the townspeople acquired it, would allow them to buy their freedom from Hatcher. This is why Hatcher wants the Gato and wants Travis free to find it for him. Travis flees into the jungle but is again captured by Beck after Travis fails to talk his way out of capture. They in turn run afoul of a group of rebels led by Mariana (Rosario Dawson
), a town clerk with whom Travis is infatuated. Beck agrees to let Travis find the Gato for Mariana before he takes him home, and with the assistance of the rebels, the three find the location of the Gato and retrieve it. Travis is eager to donate the artifact to a museum despite his greedy tendencies, but Mariana incapacitates Travis and Beck with a toxic fruit and takes it, unwilling to allow Travis to keep it.
In the morning, Beck returns to the airstrip to take Travis home, but finds out that Hatcher has captured Mariana. Reluctant to leave after his agreement with Mariana, Beck returns to town with Travis. After learning of Beck's return, Hatcher locks down the town and sends his men out to kill him. Hatcher's gunmen best him, so Beck reluctantly takes up his own guns and reveals himself as a skilled marksman, effortlessly dispatching Hatcher's men and freeing Mariana. Hatcher confronts Beck amidst the townspeople, who have now armed themselves, and is shot when he attempts to attack Mariana. Agreeing to leave the town, Hatcher attempts to walk away but collapses dead. Travis leaves the Gato with Mariana and the townspeople, and then Beck takes him back to Walker. After Beck returns Travis, Walker pays him, then hits and ridicules Travis. As a sort of toast to his last job, Beck feeds Walker and his men the same toxic fruit that Mariana fed to him, and they collapse in paralysis as an overjoyed Travis leaves with Beck, grateful but still irritating him. The film ends with Beck muttering "I'm gonna kill you" after Travis pretends to fight him.