The Haunter of the dark
In The Haunter of the Dark, a cult based on Rhode Island use an ancient artifact, the "Shining Trapezohedron" to summon a being from the depths of time and space (your usual Lovecraft nasty). The artifact had been discovered in Egypt by Professor Enoch Bowen before his return to the US in 1844. It was used by a cult in Providence who would stare into the glowing crystal and summon an avatar of Nyarlathotep called the Haunter in the Dark. The summoned creature demanded sacrifice in return for granting knowledge of forbidden places and information.
At the end of the story Dr Dexter, our would-be hero, throws the the artifact into Narragansett Bay in the hopes that it would permanently place it into the light of day and the stars, which keeps the Haunter at bay.
There are a number of ways we could use this, so I'll break it down into some ideas for different eras and games
For systems like In Her Majesty's Name, Pulp Alley and possibly even Dead Man's Hand if you fancied adding some oddness, you could run a number of scenarios surrounding the original story:
- A secret cult has been guarding the trapezohedron, keeping the world safe for millenia, until this group of American archeologists come along and start digging up the burial site. Can the archeologists be stopped, or will the Haunter return from the darkness?
- The artifact is on it's return journey to America, along with a number of other items, but the team need to stop off in London. A rival archeologist, cult or somesuch group decides they want something that is in the shipment and must be fought off
- Upon reaching America, the cult in Providence needs to go and find some poor souls to sacrifice. Can they kidnap enough people from the foggy streets before the police catch up to them?