Hell in Verdun

In the Battle of Verdun, a French battalion battles the Imperial German Army. On the verge of defeat, the Germans unleash a new gas. It goes awry. The gas not only kills the men affected by it but makes them come back, but not in any good way. It decomposes them fast, giving them the appearance of dead men walking. They attack any and all, eating them. With no other choice, the remaining French and German troops unite to survive.