Sorcerers. Grave-Maker Gas. A secret battle fought during World War I. The Ethereal Squadron, a Special Forces team of soldiers who wield magic, wages a secret war against the enemy sorcerers of the central powers. Florence Cavell, codename Geist, has a unique magical ability-she can become ghost-like and incorporeal-allowing her to infiltrate enemy forts with ease. But when the central powers unleash their magic corrupting Grave-Maker Gas, a deadly weapon that warps everything it touches, the war shifts in their favor. To have any hope of combating the new threat, Geist must retrieve the schematics for Grave-Maker Gas, but the production labs are in the heart of enemy-controlled territory. Together with a team of allied sorcerers, each with their own unique magical abilities, Geist must race against time, navigate deadly trench warfare, and fight against warped monsters in order to turn the tides of the Great War.