While camping in Jasper Park up North California, the couple Tom Alan Smithee and Gwen Marie Holden are attacked by a group of strangers; Tom is immediately killed and Gwen is abducted by the men to an underground facility to breed. A couple of months later, in Los Angeles, the manager of a video game company Johnny Dash invites the employees Adam Benson, Lee, Maggie, Perry, Chris Basso, Paul and Mike Chen to participate in a 'Battle Royal' paint-ball game at a corporate retreat in the Jasper Park to practice executive tactics. When they arrive at a gas station, they refuel their trucks and see a poster saying that Gwen and Tom are missing since 30 February 2008 and have been last seen in Jasper Park. They head to a former military reservation area in the national park and camp. During the night, Adam has the sensation that the group is under observation and he unsuccessfully warns his colleagues. When the game starts on the next morning, the group finds that their training is more than a paint-ball game, but a fight for survival in a hostile ground whose inhabitants are maniac lunatics.