War brings chaos, fear and disruption in its wake...perfect conditions in which terrible things can thrive...with new opportunities for ancient beings and their degenerate human agents. But some people know the truth, and they find themselves fighting a war on two fronts for humanity's soul -- and its very survival.

World War Cthulhu: The Darkest Hour is a new World War Two setting for Call of Cthulhu and requires the Call of Cthulhu rulebook to play. It contains full rules for character creation and wartime activities, extensive background on the setting, a scenario and an epic campaign.