“It comes up from below,” he said. “There must be a subcellar. Let’s see!”

He brought back the lantern and examined the floor by its light, going down on his hands and knees.

“Stand back!” he said suddenly. “It’s a trapdoor. See—here’s a ring to lift it.”

Captain Grey pulled at the ring, but nothing happened.

“I’m on the wrong side,” he said.

Moving over, he pulled again, and a square of stone lifted. A clear light came from below, showing a short ladder clamped to the floor.

“Stay there, please,” he told Lexy. “You have the lantern. I shan’t be a minute.”

But as soon as he had reached the foot of the ladder, Lexy climbed down after him; and just at the same moment, they saw—

They were standing in a tiny room with roughly mortared walls. A powerful electric torch stood on end in one corner, and at their feet lay the body of a man, face downward across a wooden chest. It was Dr. Quelton.

With a violent effort Captain Grey lifted the doctor’s heavy shoulder, while Lexy covered her eyes. She knew that he was dead. No living thing could lie so.