Iron Grate

A grid of dark, parallel slots cut directly into the floorboards. Metal. Cool. Sss... I crept forward, placing one square foot squarely between the iron bars. Hss! A sudden draft pushed upward from below. Air, rising straight out of the floor. I stiffened instantly. All four feet locked rigid. Silence. No trapdoor opened. The breeze was steady, whispering through the narrow slats like a quiet echo. Ssst. I leaned down, peering through the gap into the dim shaft beneath. Pure darkness, contained in straight, unbending lines. A perfect passage. I did not move.