"There's something queer about that visor," he said. Climbing on a chair he reached up to it with the poker. The piece worked on a hinge, he pushed it upward, and with a soft rumble the iron fireback in the hearth slid aside. Behind was a tunnelled opening.
"Fine stuff!" he cried triumphantly. "Forward, adventurers! Look out for your dress, Nyla, it's a bit sooty. Hang onto my coat-tail." He pulled out his mouth-organ and gave a lively rendition of the moating song.
The passage, solidly lined with stone, was pitch dark, moist, and draughty, but there was an old candle on the mantelpiece which he managed to shield with his hands. They groped cautiously through with no more mishap than a few mudstains. Eventually they reached a flight of stone steps where a crack of brightness showed above. A little vigorous pushing and the Colonel burst through a trap door. They were in a small summerhouse, discreetly screened by rhododendrons. Two hundred feet
