The Quadrant of the Chronos-King

The back wall of the chamber is dominated by a massive, circular brass door featuring four rotating gears, each bearing a unique celestial symbol. An oily sheen coats the intricate brass latticework, and the rhythmic, heavy thumping of a mechanical heart echoes through the stone floor. Above the gears, an inscription is etched into a silver plate, its letters glowing with a faint, amber light. Small steam vents hiss at the edges of the frame, releasing puffs of white vapor that smell of scorched copper and ancient grease whenever the gears are manually nudged.