Deliver them from evil
In the middle of World War I, nine British soldiers caught behind enemy lines seek refuge in a complex network of German trenches. What they soon discover is that they aren't alone - and it isn't a German soldier that's hunting them down.
In 1917, in the Western front, a group of survivors of the British Company Y reach the most forward German trench in a foggy night. They capture a German soldier that advises that evil is in the trench, forcing the soldiers to kill each other, and asks them to leave the place. Only the private Charlie Shakespeare listens and helps the prisoner, while a supernatural force scares and makes the soldiers insane.
In the brutal trench fighting of the First World War, a British Infantry Company is separated from their regiment after a fierce battle. Attempting to return to their lines, the British soldiers discover what appears to be a bombed out German trench, abandoned except for a few dazed German soldiers. After killing most of the Germans, and taking one prisoner, the British company fortifies to hold the trench until reinforcements can arrive. Soon, however, strange things being to happen as a sense of evil descends on the trench and the British begin turn on each other.