I have in mind to set this story in modern day Egypt. The time could be either now or possibly in the early 40's. Before the advent of cell phones and modern computers.
Let's make this a mystery! YC is an archaeologist, or an anthropologist, or even simply a tourist. He is exploring the ruins of a Temple in the desert and falls through a trapped door. Falling through a rough and dusty tunnel he ends up in a chamber far below the surface. In the pitch black of the chamber he hears something moving besides himself. Frantically he searches his pockets for a match or lighter, or a flashlight.
When he has light he is astounded to see an ornate altar. A bright golden torc lies on a velvet cushion. Beside it is a statue of a cat. Black and slick, it has glowing green eyes, which seem to follow him. The noise he heard was the slither and hissing of a venomous snake. He is perhaps frozen in fear when he hears the sibilant whisper. "This snake will not harm you. The torc is power. If you take it, you can control your fate. Take charge of your destiny, remake the world to what you desire. Riches and comfort await you, servants and minions to do your bidding. Go ahead, take it."
Will he take the torc and wear it? If he does, he will realize the power comes with a price. He will be forever cursed to fulfill the insatiable needs of the demon who offers it. He will have slaves and an army of hellish minions. He will be forced to kill and conquer the world he is suddenly tossed into. Not the world he came from, but an underground world of wonders. The walls around him fall and he is suddenly surrounded by his servants.
Oh, did I mention the Guardian? The black cat statue is the Guardian put there by Bastet, the Egyptian Goddess. As soon as he grabs the artifact she will come alive and attack him. She leaps at him from the altar to retrieve the artifact.
But his minions block the attack and he is able to escape. Running into the huge underground city, he takes refuge in the Palace and is hailed as the new King. The cat is forced to fight for her life. She cannot stop him now, but she will continue to hunt him and try to retrieve the torc.
Of course she is not alone. Other devout servants of Bastet will help her. The entire rp will be the story of the chase and YC's efforts to either go along with the demon and do his bidding or maybe he is fighting against it and trying to rid himself of the torc. Maybe he is torn in different directions? Is he a good man deep down and wants to do the right thing? His minions bring him slaves they have stolen from the world above. What will he do if they suddenly bring him members of his family or friends who have been searching for him?
So much we could do with this. I want someone with lots of creativity and a willingness to keep the story interesting. Send me a PM with your ideas!