"You wouldn't murder me - not in cold blood. "Let's leave it up to the kids." The piercing blast of the whistle echoed, reverberating from the rounded iron walls beside me and below. Out of the corner of my eyes I saw the five figures moving toward the platform on which we stood. Their laughter was demonic. "Call them off!" I shouted. "I warn you --" He shook his head. Closing my eyes, I concentrated. There are subsonic whistles which make no audible sound, and there was ways of summoning which require no whistles at all. And there's more than human vermin infesting abandoned sewers, lurking in the far recesses of tangled tunnels, responsive to certain commands. The rats were coming.