An American corporation sets up operations in Mongolia to search for shale oil by pumping superheated water into the earth. The project encounters mysterious mechanical failures and delays while at the same time, the on-site manager, Patrick, is worried that the equipment failures and delays will attract too much attention from corporate. The drilling operations have disturbed a nest of Mongolian death worms that are known in the legends of the indigenous people—monstrously long and lethal creatures that tunnel underground, similar to the creatures graboid seen in Tremors, though slimier looking, with an enormous maw of teeth, poisonous venom, and the ability to generate an electromagnetic field that interferes with communications and other equipment. One of the oil field workers is attacked and killed. Other workers, frightened by the rumors, don't show up for work. With the drilling operation (and his side deal) threatened, Patrick starts to panic when Mr. Bixler from corporate shows up to find out what's going on.
At the same time, a group of volunteer medical workers, Doctors of Hope, is trying to stop an outbreak of disease in a Mongolian village also caused by the worms contaminating the water sources. The lead doctor encounters Daniel when she and a colleague, Phillip need transportation for themselves and their medical supplies to the village where the rest of her team is working. Daniel is a target of the chief crime boss in the area, Kowlan because of Daniel's treasure hunting forays into their territory. We eventually learn that Daniel already knows about the legend of the worms and has found artifacts with engraved images of the creatures. He believes his finds will lead him to a treasure—Genghis Khan's tomb.
While transporting the two doctors to the village of Sepegal, Daniels truck breaks down and they are taken captive by Kowlan's men. A friend of Daniel's, local police officer, Timur finds Daniel's abandoned vehicle by the road and starts searching for him. Back at Kowlan's camp, Daniel creates a distraction so that the two doctors can escape. During a gun battle, worms emerge from the ground and eat Kowlan and his men. Daniel fires into a fuel tank and blows up one of the worms. Alicia and Phillip return to get the medical supplies from Daniel's truck and continue on to Sepegal where the epidemic is raging. There, another doctor, Steffi, tells Alicia that the elderly sick people have been insisting that the epidemic is caused by the "death worms." Alicia and Phillip haven't actually seen any worms, but they heard Kowlan and Daniel talking about them.
At the plant, Patrick, desperate to still make his black market deal, reveals his duplicity when he pulls a gun on Mr. Bixler, who is on the phone to corporate. Patrick ties him up in the office. Shortly thereafter, another corporate manager shows up and, while looking through the plant for Mr. Bixler, is promptly eaten. . Patrick, still unaware of the worm threat, takes Bixler down to the lower level and binds him to a support column and gags him. Daniel reaches his truck and then goes to Sepegal to warn Alicia about the worms, Daniel insists they need to move the temporary clinic and its patients somewhere else. One of the local people, a nurse, says they could find a phone and help at the oil drilling facility not far away. When they arrive at the plant, Daniel and Alicia are confronted by one of Patrick's people, Bana, only participated in the theft scheme to help his people, he lets Daniel and Alicia inside when a worm appears behind them, ready to kill. Alicia theorizes that the worms are a type of organism that has been released from stasis because of the pumping of hot water deep into the earth. If the pumping stops, no new worms should be 'hatched.' Daniel. In Sepegal, Phillip and the nurse, Thuan are drawing water from the well when Thuan is sucked in by a worm and killed. Phillip and Steffi run back to the hospital as the worms begin to surround the hospital.
At the plant, Daniel and Bana shut down the pumps, then Bana panics and runs away, leaving Daniel behind. As Bana emerges from the plant, Patrick and the other accomplice return from having taken a crate of stolen loot to another hiding place. Bana yells at them to leave, that it's too late to go back inside, but as he runs to the truck, Patrick shoots him in the back. He then discovers Alicia in the plant office; she is on the phone with Officer Timur explaining that Sepegal needs help. He rushes to Sepegal and kills several worms Timur tells the staff that more help is on the way, then he waits in the clinic with the staff and patients.
Daniel goes down lower levels of the plant. He then finds what he has been seeking, Genghis Khan's tomb. Patrick shows up, gun drawn, while his associate has Alicia at knifepoint. Daniel has to put his gun down. He distracts him by pointing out the remains of Mr. Bixler and then get into a wrestling match. Daniel shoots Patrick in the shoulder. The ground shakes and worms begin to emerge from the walls. Patrick's henchman is eaten, and Daniel realizes this is the queen worm's nest and the entire place must be destroyed. Timur arrives at the plant to find Daniel and Alicia and discovers Bana's body outside. Daniel discovers the room full of crates holding the treasure of the tomb. He breaks open a crate and artifacts and gold pour out onto the floor. Alicia reminds him that it isn't worth dying for, and he agrees that they must destroy the plant completely. Patrick limps into view, bleeding badly. Timur appears with shotgun in hand. Behind him the queen creeps up and eats Patrick. Daniel and Alicia attempt to make the pressure build up in the generators and pipes. Just as they are about to escape the building more worms show up. Timur shoots them, but is eaten by the queen. Daniel and Alicia rush outside as the explosions go off. Daniel returns Alicia to Sepegal and her colleagues. Daniel says he is going back to collect the treasure from the field around the plant.
- Sean Patrick Flanery as Daniel
- Victoria Pratt as Alicia
- George Cheung as Timur
- Drew Waters as Patrick
- Matthew Tompkins as Mr. Bixler
- Nate Rubin as Phillip
- Jon Mack as Steffi
- Cheryl Chin as Thuan
- Tiger Sheu as Bana
- Ryan Manalansan as Tali