An elite group of soldiers led by Mack (Cuba Gooding Jr.), are sent by a CIA agent named Elissa Cardell (Valerie Cruz) to rescue her father, a scientist named Wesley (Ron Perlman), who is working on an archaeological dig in the Middle Eastern desert. When they enter the dig site, which is a large underground laboratory, they encounter a priest who has strange boils all over his body. The team's medic, Doc (Taryn Manning), sedates the priest. Click (Brandon Fobbs) uses the dig site's terminal to activate the elevator and notices something codenamed the Gehenna Project. He asks Cardell if she knows what it is but she denies knowing about it. Mack orders Nickels (Zack Ward) to stay and watch the priest while the rest of the team takes the elevator deeper into the dig site.
When they exit the elevator they encounter a scientist named Duncan (Bill Moseley), who has strange boils like the priest. Duncan attacks Hammer (Franky G) but is shot in the chest by Mack. While treating Duncan's wound, Doc has a hallucination of her sister angry at her for letting her die. Duncan and Doc disappear but the team uses Doc's tracking device to follow after them. The team splits up and Yoshi (Stephanie Jacobsen) follows a hallucination of her and Hicks's (Jason London) unborn daughter. The team runs into Duncan, who is trying to open the door to the safe room. Duncan yells at the team about their ignorance of salvation and Mack shoots him in the head, which strangely doesn't kill him, but when the entire team shoots him he finally dies.
The door to the safety room is opened from the inside, revealing a priest named Fulton (Henry Rollins), who Cardell knows, and who tells them that Doc was probably taken to the temple; he agrees to take them there. The team notices that Yoshi is missing and, when they find her, she tells them of her hallucination. Fulton explains that the possessed use visions to tempt humans. Mack then duct tapes Fulton's mouth shut. Nickels hallucinates a nude woman and he is attacked by the priest; he fights back with a knife but has his arm broken and the priest spits a dark fluid into his mouth, then drags him away.
Click is separated from the team and encounters Doc locked in some room; when he tries to help her he is attacked by a possessed obese scientist. Hammer shows up and rescues Click, but more possessed start to appear, Hammer decides to throws explosives at the group, causing the passage to collapse. Fulton and the team arrive at the temple, where they learn from Fulton and Cardell that the scientists are possessed because they absorbed the spirit of one of the Nephilim, which is frozen in the temple, to prevent it from escaping. Fulton explains that the dig site is one of many tombs created by God to imprison Nephilim. Yoshi follows the hallucination to Doc, who is revealed to be possessed. She seduces Yoshi and allows her to lick strange, infectious boils on her shoulder, infecting her. Doc then cuts her back open. When the team notices that Yoshi is missing, Hicks and Hammer try to find her. During their search, a possessed Doc attacks Hammer, who aims his gun at her after he notices that she has developed boils. Hicks points his gun at Hammer, who tries to tell Hicks that Doc is possessed. Hicks doesn't believe him and shoots at Hammer, who manages to run away.
Hicks then chases Doc and finds Yoshi, whose spine is exposed. He tries to help her but she attacks him, and then Doc rips his throat out. Hammer arrives back at the temple to tell Mack about Doc and Hicks.
Fulton realizes that, with Click's unintentional help, Cardell activated the Gehenna Project, which is a self-destruct device for the dig site. He runs for the elevator alone. The soldiers only have fifteen minutes to get to the elevator before the explosion. The door to the temple slowly starts closing. Mack, Cardell, and Click make it out of the temple but Hammer gets locked in and, surrounded by possessed scientists, he puts up a fight, but he is overwhelmed and sets off his grenades, killing himself and the possessed scientists attacking him. Fulton is pushed into barbed wire by Doc, who then slits his throat.
Mack, Cardell, and Click arrive at the area where they encountered Duncan for the first time, and they meet up with Wesley, who is possessed but doesn't have the boils. Doc and Nickels, who is now possessed, arrive and Mack and Click shoot him and a few other possessed until the possessed priest grabs Click, drags him away and kills him. Mack has a hallucination of his old best friend Blakeley (Ray Winstone), who Mack was ordered to murder years ago. Mack resists and shoots an explosive barrel next to Wesley which burns him and kills Doc, along with the hallucination of Blakeley. Cardell stands over Wesley and sets his soul free. When Mack tells her that they have to leave she refuses, saying that her goal was to set her father's soul free. Mack makes it to the elevator alone and escapes from the dig site seconds before the explosion. Mack is then picked up by the helicopter and realizes that he has a new purpose in the world, that he is a new soldier in an ancient war.Cuba Gooding Jr. as Mack
Ray Winstone as Blakeley
Taryn Manning as Doc
Ron Perlman as Wesley
Valerie Cruz as Elissa
Henry Rollins as Father Fulton
Bill Moseley as Professor Duncan
Zack Ward as Nickels
Dania Ramirez as Shanae
Franky G as Hammer
Stephanie Jacobsen as Yoshi
Brandon Fobbs as Click
Jason London as Hicks
Filming began in California from November 2007 to January 2008, on a $10 million budget. The film received an R rating from the MPAA for strong violence/gore, language and brief nudity.
The DVD was released on May 26, 2009 in United States, distributed by DreamWorks Pictures. The special features included on the disk are a directors commentary, outtakes, a making of documentary, deleted scenes and alternate scenes. As of August 14, 2009, it had sold 159,568 copies and grossed $3,189,764 in sales.
The DVD was released in Australia on December 9, 2009.