Balin followed the ancient passage, his torch glittering on damp walls. He was in one of the oldest sections of Khazad-dûm, dating back to Durin the Deathless himself. It had long been sealed by a rock fall, most likely soon after it's construction. Only the very oldest maps included this network of tunnels.
He'd heard whisperings, rumors, that one of the dwarf-rings had been hidden here in an ancient passage, but the exact location had been lost in the fog of time. Still, if the ring really was here, Khazad-dûm would not show its secrets so easily.