They went out to the head of the drive to meet him, and Mary offered her theory.

“I must have been mad not to have told you about this before. I don’t know where my wits have gone,” she said. “After all my treasure-hunting and the horrible experience I had that night with Gilder, and not to think of it now, when I practically came down to show Mr Gine the place – well, I’m surprised at myself!”

Dick listened with growing impatience to this preliminary.

“Where do you think my brother is?”

“Where?” said Miss Wenner triumphantly. “Why under the abbey – that’s where. I’ll show you.”

They walked side by side across the meadow, and as they went Miss Wenner related the startling story of her adventures after treasure.

“Of course, I always knew that it didn’t belong to me, even if I found it,” she said virtuously; “but Mr Gilder was so very pressing that I couldn’t very well refuse him, especially after what he’d written in vanishing ink, though I’ve got the ink back again, as he’ll find out one of these days.”

Leslie listened, scarcely crediting her ears. Yet, unless Mary Wenner had an imagination of a particularly inventive nature, it was hardly likely that she could have made the story up.

Dick examined the great corner-stone of the tower. He stood by, watching curiously, whilst, with a pair of scissors which she took from her bag, the girl pressed back the catch and sent the corner-stone turning noisily on its invisible hinge.

The opening was between twelve and fifteen inches wide. A stout man could never have entered by that way, as Dick pointed out.

“You had better stay here; I’ll go down,” he said.

“You’ll want a light,” warned Mary.

There was a lamp in his pocket. He had spent the morning peering into impossible dark places. In a second he had disappeared down the moss-grown stairs, and Leslie waited with palpitating heart for his reappearance. Presently they heard his voice.

“Come down.”

“Not me,” said Mary hastily. “I’ve been there once, thank you!”

And Leslie went alone, guided by the light he showed from step to step.

Now she was standing with him in the vaulted room. He tried first one and then the other of the two doors leading from the antechamber, but neither yielded to his touch. It was pitch dark save for the fan-shaped ray of the lamp. He swept the light along wall and floor, and presently she saw the focus halt upon a broken flagstone.

“What is it?” she asked.

“Nothing,” he said quickly. He had moved the light to the narrow entrance of the room. “Up you go; there is nothing here but mice and memories. I have always known there were underground vaults in the abbey. In fact, I think there was a report on them by one of my recent forbears.”