It was well after one o’clock in the morning when Dr. Silence turned the lamp out and lighted the candle preparatory to going up to bed. Then Smoke suddenly woke with a loud sharp purr and sat up. It neither stretched, washed nor turned: it listened. And the doctor, watching it, realised that a certain indefinable change had come about that very moment in the room. A swift readjustment of the forces within the four walls had taken place⁠—a new disposition of their personal equations. The balance was destroyed, the former harmony gone. Smoke, most sensitive of barometers, had been the first to feel it, but the dog was not slow to follow suit, for on looking down he noted that Flame was no longer asleep. He was lying with eyes wide open, and that same instant he sat up on his great haunches and began to growl.

Dr. Silence was in the act of taking the matches to relight the lamp when an audible movement in the room behind him made him pause. Smoke leaped down from his knee and moved forward a few paces across the carpet. Then it stopped and stared fixedly; and the doctor stood up on the rug to watch.