I searched the room and discovered that one of the stalagmites protruding from the floor was slightly worn around the tip. I grabbed the stalagmite and pulled it toward me, but it didn’t budge. I tried pushing, and it gave, bending as if on some hidden hinge, like a lever. I heard a rumble of grinding stone behind me, and I turned to see a trapdoor opening in the floor. A hole had also opened in the roof of the cave, casting a brilliant shaft of light down through the open trapdoor, into a tiny hidden chamber below.