Vince (Tom Sizemore) heads a maintenance team sent underground to fix a mechanical snafu but discovers a much more dangerous problem when a mysterious creature starts hunting them down. As the terrified group searches for a way out, they learn that the bloodthirsty monster is the result of a military experiment gone bad. Seemingly impervious to all their attacks, the beast locks Vince in a desperate battle to save his crew from a gruesome fate.