Nyxin moved through the dark like he belonged to it. Silent boots on cracked linoleum. A thin beam of light from his penlight cutting through the black, sweeping over overturned gurneys and walls stained with something that had dried too long ago to identify.

The files were supposed to be in Administration Hall B. Three floors down. Simple retrieval. Standard intel.

He reached for the handle.

Then he heard it.

A sound from behind the wall. Not pipes. Not wind. Something rhythmic. Soft, but deliberate.

Tap. Tap. Tap.

Then a voice. Thin. Broken. Like it hadn't been used in a long time.