The passage opens at last into the source of the hissing. Steam rolls across a circular chamber, and the ancient pressure valve coughs in steady breaths along the wall. The sound matches the haunting rhythm that has followed them down.

Kynes steps into the clearing steam. At the room's center, a pedestal rises from the stone, holding a dormant crystalline mechanism, its facets dulled by age and dust.

The glass key warms in his hand. When Kynes brings it near, the crystal on the pedestal answers with a faint violet pulse, as if recognizing a long-lost twin.

Kynes fits the glass key into the mechanism. The chamber shudders once, then the dormant crystal lights from within, and the valve's hissing settles into a deeper, deliberate tone.

A hidden seam opens behind the pedestal, revealing a downward stair and the dark path the lock has been guarding all along.

Kynes turns his head toward Bren, the side-eye catching her right as the stair seam breathes cold air below them.

Bren lowers her blade a fraction and leans toward the opening, listening to the stone as if it might answer first.

Her mouth twitches at that, then steadies. The violet glow from the mechanism paints her face in hard angles, and she looks back at Kynes as if measuring how much he is willing to trust.

Kynes peers into the yawning throat of the stairwell, but the violet light from the mechanism fails to penetrate the thick, swirling gloom beyond the first few steps. The darkness ahead remains absolute, swallowing the beam of his staff and refusing to yield any detail of the path below.

Kynes lowers his staff a fraction, the remark settling into the damp hush. The violet glow still licks the pedestal behind him while the stair remains buried in black silence.

Kynes raises his staff and threads a spell into the dark stair. Pale motes bloom from the tip, then split into a slow cluster of blue-white lights.

The lights drift forward in a careful line, skimming the first steps and revealing slick stone, a broken edge, and a narrow landing below.

The violet glow from the pedestal answers the new light, and the stair’s blackness finally gives way to a faint, honest shape.

A thin draft climbs from below, tugging the drifting lights downward as if something deeper wants them to follow.

Kynes lowers the staff and steps onto the first lit stair. The blue-white lights drift ahead of him, obedient and slow, marking each drop in the broken spiral.

Bren falls in behind him, one hand hovering near the wall, her gaze fixed on the moving glow and the blackness beneath it.

Stone dust loosens under Kynes's boots. The hidden stair answers with a faint tremor, but the path stays open.

The violet pulse from above fades behind them as the chamber mouth shrinks to a cold ring of light.

Far below, the drifting lights reveal another landing, and beyond it, a narrow seam in the stone where the stair bends out of sight.