It is 1917, and a handful of survivors from Y-Company are utterly lost behind enemy lines in the Western Front. They find shelter in an abandoned enemy trench—a claustrophobic maze of blind corners and underground tunnels, overflowing with war dead and infested with rats. It is here the survivors of Y-Company wait to be rescued. But as night draws, nobody comes. They begin to think there is someone...or something in the trench with them. One by one, the young men die as an unseen stalker terrorizes and preys upon their fear.