Western Front, 1917. In the chaos of a trench war battle, a small company of men get lost, surrounded by a thick mysterious fog. As they emerge from it, they come across a deserted German trench. Convinced they have broken through the enemy lines, they decide to secure the trench and begin to explore it. Only to find mutilated German corpses everywhere. Something very strange and evil has happened here. When one of them is found horribly murdered, wrapped in barbed wire, they know they are not alone!