The Midnight Game By Cynthia Murphy

Rules of The Midnight Game:
Do not turn on the lights.
Do not go to sleep.
Do not leave the building.
When a group who have met on a creepy Deddit thread decide to meet in real life, they only have one plan in mind: they are going to summon the Midnight Man. And once you start the Midnight Game, you must finish it - there's no other way out! Six strangers. One night. But how many survivors?