Or as I was originally going to entitle this post, "The Thing in the Trenches".

The first World War had terrors aplenty, from the debilitating chemical burns of mustard gas attacks to the mounting dread of wondering if today will be the day you receive the order to go "over the top". But in the milieu of the Cthulhu Mythos, the practical, moral, and existential fears brought about by the war to end all wars are but the first layer of the onion. When the horrors of war and the horrors of the cosmic unknown combine, the stage is set for a different gaming experience. With that said, I present the following adventure hooks for Cthulhu Mythos games set in the Great War.

The Silent Trench

In the trenches in Europe, a telegraph station has gone silent. The Investigators (comprised of soldiers, officers, engineers/technicians as appropriate) are sent down the line to discover the cause. They discover an unmanned length of trench and an undamaged telegraph. For those who dare to peek over the top, the remains of soldiers are seen who were gunned down while attempting to flee the trench. The cause of these strange occurrences is a seemingly bottomless cavern - a ghoul warren - exposed by an enemy mortar. Now that the ghouls have had a taste of war-seasoned flesh, they will surely pour forth into the trench network for a feast of epic proportions.

The Circle Unbroken

Observation balloons have made an odd discovery. A strange arrangement of shapes is being dug into a hillside behind allied lines. The investigators (composed of soldiers, intelligence officers, locals familiar with the lay of the land as appropriate) are dispatched to see if this is some sort of enemy plot or an elaborate prank. In truth, the strange shapes are the foundation for a massive ritual circle being created by cultists of Shub-Niggurath who were driven from their traditional sacred ground by one of the first big pushes of the war. The cult now hopes to consecrate a new ritual site for their seasonal rites, and the investigators may arrive just in time to be the first sacrifices, or just late enough to witness the avatar of Shub-Niggurath called down.

Maze of Death

A large portion of the enemy line has been captured, and the Investigators are among the personnel dispatched to secure it. While assessing the area, an entrance is discovered connecting a network of catacombs to the trench works. Evidence suggests the catacombs were used as part of the supply chain, munition's storage, and battlefield laboratory before abandoning it and boarding it up. In truth, these catacombs connect to a nearby medieval fort that burned down during the early days of the war. Now the catacombs are home to the fort's former master, an immortal alchemist who has elected to ride out a chaotic century in a deathly sleep in a tomb/laboratory deep in the catacombs. Old spells and alchemical creations lurk deep in the catacombs protecting their master, as well as his laboratory and collection of arcane texts. It is only a matter of time before the sanctum and the sleep of its occupant are disturbed.