Song Ning crouched down just as he had.
The floor was concrete, the same mottled, oppressive gray as the walls.
The old-fashioned light bulb cast a yellow glow, no matter how high its wattage.
Without looking closely, it was hard to notice the footprints on the floor.
She hadn't noticed until he mentioned it, but once she crouched down for a closer look, sure enough-
Numerous shoe prints crisscrossed the floor of this room, the emptiest of them all.
They were especially plentiful in the open space toward the back, even along the walls.
It looked as though-
A lot of people had gathered here.
With that question in mind, Song Ning went to inspect the other rooms.
There were footprints in all of them, of course, but nowhere near as many as in the last room.
When she returned to the seventh room, Gu Zheng was crouched in a corner, examining something closely.
"Gu Zheng! Did you find something?"
"Come take a look!"
Gu Zheng pointed to where the wall met the floor and said,
"Isn't there a gap between the wall and the floor?"
Song Ning looked where he was pointing, then quickly stood and walked a circuit of the room along the walls.
She turned to Gu Zheng and said excitedly,
"Gu Zheng! I think this room's entire floor can move!"
Gu Zheng nodded. "Looks like this is where the mechanism is! There isn't a hidden compartment between the rooms. There's another space underground."
Their confidence soared.
But afterward, they checked everything in the room, even feeling over the walls again, inch by inch.
They still couldn't find anything that activated the mechanism.
There were no recesses, buttons, keyholes, or anything resembling a combination dial.
How had those people activated it?
Song Ning felt over the large