Knock, Offer, Enter

You find a circular chamber of damp stone, its walls bending subtly as though the room is being carried inside a moving thing. Green candle flames lean toward a black altar at the center. Three relics rest on wooden tracks before it: a bone bell, a bowl of cold red liquid, and a lantern whose light reflects distant roads, moonlit marshes, and unfamiliar doors. A broken ring of chalk, salt, and black thread surrounds the altar. Somewhere beyond the walls, heavy footsteps pass overhead, followed by a woman's muffled humming. Each time someone touches a relic, the chamber gives a quiet lurch and one of the altar symbols briefly glows.