A Bounty Hunter Travels To The Amazon Jungle To Seek A Mobster's Son

 "The Rundown" aka "Welcome to the Jungle" opens with Beck, a "retrieval expert", a bounty hunter who collects debts for a man named Billy Walker.  

He is dispatched to a nightclub to retrieve a championship ring from a football player, Brian Knappmiller, as collateral until he fulfills his payment. Unfortunately, he gets laughed at and embarrassed in front of everyone as the man spills alcohol all over him. He is quickly told to get out. Beck goes to the restroom where he calls his boss, Walker, and asks to do it another night, as the entire football team is there and he doesn't want to hurt them too badly. Walker tells him to do it anyway. Beck returns to Brian's table and gives him two choices, either to give up the ring voluntarily or Beck makes him give it. Brian picks option B, and a brawl ensues, with Beck knocking out his friends one by one. Even taking some out by performing his signature move,  the Rock Bottom. After taking out all the goons, he grabs Brian and takes the ring off his finger.

After leaving the club Beck gets assaulted and incapacitated by one of Walker's other collectors,  who steals the ring from him. Angry, he drives to Walker's home and confronts him. He tells him that he wants out of the business. Walker talks him into one last bounty - to retrieve Walker's son, Travis, from a small mining town in Brazil, in the Amazon rainforest. Travis is a treasure hunter who pissed off the wrong people. By doing this last job, Walker will give Beck enough money to open his own restaurant. Beck reluctantly accepts and leaves for Brazil. He travels in a small plane with his pilot and guide, Declan. The plane is barely in shape as it's wrapped around with duct tape and shakes violently. They manage to land safely and they make their way to the town of El Dorado. Meanwhile, Travis walks into a bar to ask the bartender, Mariana, for another favor by borrowing her boat to look for a missing golden artifact called "El Gato de Diablo”. Mariana is tired of Travis, as he always borrows things from her for his search and returns them in less-than-ideal shape. She agrees,  but only if she comes with him and they split the profit 50-50. Having no other option, he agrees.

Beck meets with the man running the mining operation, Cornelius Hatcher. Hatcher shows Beck the view to his mine, which Beck refers to as a hellhole, where tens of thousands of people work like slaves, but Hatcher says that what some see as hell, he sees as an opportunity to make a huge profit. Hatcher then gives Beck his blessing to grab Travis if he pays him $10,000. Beck agrees and tells Declan he is buying his jeep for $1,000 and tells him to wait for him on the plane. Beck arrives at the bar and gives Travis option A to come back quietly or option B to get forced back on a plane to Los Angeles. Travis says he picks option C and tries to attack Beck, but quickly gets restrained and handcuffed by Beck. Suddenly, Hatcher comes in with his men and says the deal is off and that Travis stays since he found out about the golden artifact that Travis might've found. One of Hatcher's men, Harvey, gets confrontational with Travis and asks him if he really found the artifact, but gets told to back off by Hatcher. Hatcher then gives Beck a chance to leave without getting hurt, but without his $10,000, as he sees that as tax-deductible for the health benefits of Beck. Beck scoffs and starts to leave, together with Travis, but Hatcher's men get confrontational. A brawl ensues, with Beck throwing Hatcher's men across the bar and then making a run for it with Travis. On the way back to the airfield, Travis attempts to double and quadruple his father's payment on Beck, but when Beck refuses, Travis ends up forcing their Jeep off the road and into the jungle below. They fall down for good 5 minutes until they finally hit a waterfall below. Travis tries to escape while Beck is incapacitated, but Beck quickly catches up.

Travis confronts Beck and decides to fight him for eyeballing his woman. Unamused, Beck knocks him down with one punch. Travis tries his luck a few more times until Beck finally subdues him and handcuffs him again. Travis then tries to convince Beck of the Gato artifact and how priceless it is and that they could share the profit, but Beck is not interested. After a few hours of walking through the jungle, Travis stops and demands that he pee. Since his hands are tied behind his back, Beck unzips him and he goes for it, but he has problems getting it out. While he struggles to pee, Beck walks around and ends up stepping on a trap, which ties his ankle and leaves him hanging upside down. Travis makes fun of him until he starts to walk away and steps into the same trap, which leaves him hanging next to Beck. As the duo works together to try and free themselves, a loud screech interrupts them. Suddenly, a group of violent monkeys starts attacking them, as they swing back and forward. A monkey climbs on Beck's face and starts dry-humping him. A sudden gunshot from a rebel group scares the monkeys away.

They are then taken to the camp of the local resistance movement. Travis convinces the rebels in Portuguese, that Beck works for Hatcher and was sent to kill them all. After a prolonged fight with 10 of the rebels, Beck gains the upper hand before Mariana intervenes. We learn she is the rebel leader and that she wants Travis, as the Gato can be used to ensure the locals can free themselves from Hatcher,  who keeps them working the mine as slaves for 65 cents an hour. Hatcher suddenly attacks the camp,  killing many rebels. Beck, Travis, and Mariana escape the camp by boat. Beck makes Mariana a  deal: Travis will show them where the Gato is, which she wants, in exchange for her help to get out of the jungle and lead them to the airfield. Having no choice, Travis is forced to lead them there. After an extensive walk through the jungle and some searching, Travis leads them to a cave behind a waterfall where the Gato is located. They retrieve it, just as the cave starts to collapse. On the way back, Mariana chastises Travis for wanting to sell the artifact, but Travis argues that he actually wanted to give it to a museum. Mariana gives the unsuspecting men Konlobos, a toxic fruit that temporarily paralyzes the eater. As the fruit's toxin takes effect and paralyzes them for the next several hours, she tells Beck which direction the airfield is and leaves them with the fire to keep the animals away.

The next morning, the paralyzed duo is greeted by the humping monkeys who scream loudly. Beck is able to scare them away as he screams louder. Beck then hauls Travis to the airfield. Just as they get ready to board, the pilot, Declan, tells Beck and Travis that Mariana was captured earlier by Hatcher and will probably be killed alongside the rest of the rebels. Beck feels obligated to help Mariana since they made a deal earlier and he starts heading to town when Travis stops him and pleads to come and assist him, as Beck doesn't know his way around the town and refuses to use guns. Beck reluctantly agrees and the two head into town to rescue her. Having lost contact with one of the outposts, Hatcher sees Beck on one of the cameras and Beck tells him that he has 2 options, to either let Mariana go with the Gato and leave town or the second option,  where Beck makes him. Hatcher and his men laugh at Beck until Beck knocks out the camera before saying he picked the wrong choice. Hatcher puts his men on alert and locks down the town. Using a cow stampede for cover, the two begin their assault on Hatcher's goons. They dispose of many mercenaries until Travis becomes trapped by gunfire in a bus, forcing Beck to save him by using guns before the bus explodes. Beck becomes the embodiment of a Terminator and starts disposing of the mercenaries one by one, even disposing of snipers with a shotgun from afar. Hatcher tells Harvey to take Mariana and the Gato and flee, but they are stopped by Travis who bumps into their car and forces Harvey to flee, leaving the Gato behind which Travis picks up. The next scene is great. A sniper takes aim to shoot Beck, just as Hatcher makes his way over to personally kill Beck, but Travis kills the sniper first, who drops the sniper rifle, which Beck picks up and shoots Hatcher's gun off his hand. Beck still gives him the chance to leave town, which Hatcher initially refuses. After he is shot by the townspeople, Hatcher agrees to leave town but eventually dies from his gunshot wounds. Mariana thanks Beck, but they both believe they lost what they really wanted out of the deal, which was Travis and the Gato, thinking he has fled. Suddenly, Travis shows up and gives the Gato to Mariana before leaving with Beck, who tells him that despite all they've been through he must still return Travis to the United States. 

Travis is delivered to his dad who begins to verbally and physically abuse him right from the door. Beck asks to celebrate with them and gives Walker and his men Konlobos. As they are paralyzed,  Beck uncuffs Travis, and the duo leave together, with Travis continuing to jokingly annoy Beck.