Ireland, 1209. An island on the edge of the world. A small group of monks begin a reluctant pilgrimage across an island torn between centuries of tribal warfare and the growing power of Norman invaders. Escorting their monastery's holiest relic to Rome, the monks' progress is seen through the eyes of a pious young novice and a mute lay-brother with a violent past. As the true material, political and religious significance of the bejeweled relic becomes dangerously apparent, their path to the east coast becomes increasingly fraught with danger. The monks belatedly realize that in this wild land of ancient superstitions, the faith that binds them together may ultimately lead to their destruction.

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.