You are a team of paranormal investigators working from Miskatonic University where you track the expansion of 4 doomsday cults across the North American continent. Your mission is to prevent these cults from opening cosmic gateways that will summon Great Cthulhu from his slumber in R'lyeh and usher a new age of human suffering, culminating in the utter destruction of the world as we know it
Players must work cooperatively to mesh their investigators strengths, rooting out and exposing each cult to the cold light of judgment. But the cults are migrating and expanding at a frightening rate and time is running out: the team must try to expose all four and prevent the gateways from opening. If the cults are permitted to spread unchecked, the players all lose. If they can find ways to expose all cults while retaining their sanity, they win.
But unspeakable horrors lurk in every shadows, and traitors may be closer than the players realize... .
The board shows the North American continent with both widely and sparsely populated areas. On each turn a player can use four actions to travel, remove, expose and build. Cards are used for this but the deck also contains horrors from the Lovecraft Mythos and the dreaded rallying call of cultists, "Cthulhu Fhtagn!" ...