For myself, I had been so stunned that I couldn't think, but my friend's despairing call seemed to jerk some cog-wheel within the brain and start again the mechanism of thought.

I gripped him by the shoulder.

"There isn't a soul here," I rasped out. "What does it mean, what on earth does it mean?"

"There should be three hundred at least," he answered.

I broke away at a run, flung open the first door I came to and peered in. It was some sort of a sleeping-room, there were bunks and couches all around the walls. Each one of them was empty. I had time to see that, and also that a stand of short carbines and cutlasses was full of weapons.

Then I had to back out quickly for the late inmates had left an odorous legacy behind them.

Pu-Yi faced me.

"That was one of the patrol rooms," he said.

Then I remembered our coming two days ago.

"Mulligan!" I cried. "Nobody could get here except through the guard-room, nobody could leave here except through that, could they?"