Achtung Cthulhu: Investigator's Guide
Achtung Cthulhu: Investigator's Guide - Rules of Play says:
In the Achtung! Cthulhu universe, a band of Allied heroes fight the Secret War against the Nazi Black Sun and their rivals Nachtwolfe. Powered with ancient secrets and terrible Mythos allies, Black Sun and Nachtwolfe are on the verge of unleashing terrible weapons upon the Allied forces.
You'll be able to follow their exploits through the roleplaying games, boardgames, graphic novels, audio adventures, wargames, card games and much more. It all starts with the Achtung! Cthulhu Investigator's and Keeper's Guide which are you gateways to the world of Achtung! Cthulhu