There is – by certain unreliable and maddening accounts, and now by your own dreadful experience – a city on the eastern seaboard of the United States, in northern Massachusetts. You do not recall seeing it on maps when you were growing up, and no-one of your acquaintance ever admitted coming from that place until you found yourself living within its eerie confines. It is a city of windowless cyclopean skyscrapers, of crumbling baroque buildings and ruins that must, impossibly, predate human habitation in this part of the world. At times, you can see remnants of familiar small towns that have grow together into this monstrous conurbation – Dunwich in the west, beyond Sentinel Hill; quaint Kingsport, by the sea; industrial Innsmouth, the engine of trade and commerce; and the city’s heart, Old Arkham.
You know that this city is monstrous.
You know that the city government are in the thrall of – or in league – with alien horrors.
You know better than to go out at night, when the clouds roll in from the sea and shapes move in the sky. You know there are occasional, unpredictable streets that come and go according to some unearthly schedule, that strange black ships dock at Innsmouth to trade with the squat, ugly denizens of that neighbourhood. You know, too, that not all of your neighbours are sane – or human.
But you’re trapped. There’s no way to escape the city.
Because the city is the world.
Cthulhu City is a setting for Trail of Cthulhu, usable for a full campaign in its own right or as a nightmarish intrusion into an existing game. The Investigators find themselves in a strange, corrupted Arkham, a ghastly metropolis. People – humans – live in the city, and seem bizarrely normal on first encounter – their concerns are the same mundane, day-to-day passions and trials of anyone in the modern world – but scratch the surface, and the Mythos spills forth. Motorcars drive down streets lined with sullen-eyed basalt cyclopean buildings raised by no human hand; at night, loathsome and titanic shapes move behind the clouds. It’s a city where priests masked with yellow silk proclaim the majesty of God from the churches; a city occupied by alien powers. The old-money families have names like Marsh and Whately and Curwen, and the worst crime imaginable is defying the will of the living gods.
Humans shouldn’t survive here, but they do, blindly adapting to the horror all around them. Are the Investigators dreaming? Insane? Have they travelled in time? Is this an alternate reality? An illusion? Or have they somehow had their minds swapped with denizens of the city?
Or has it always been this way, and they can no longer deny the truth?