The Echoes of the Sentinel

The chamber is a perfect semi-circle of polished lapis lazuli, reflecting the faint, pulsing glow of four large crystalline lenses embedded in a stone door at the far end. High above, a mechanical ceiling slowly rotates, depicting a stellar map that clicks rhythmically as it turns. Four heavy floor tiles, each etched with a distinct golden rune, are arranged in a line before the door. Whenever anyone approaches, the crystalline lenses flare with light in a rapid, rhythmic sequence, accompanied by distinct, melodic chimes that reverberate through the stone floor like a heartbeat.