Geoffrey recognized the deep rasping tones of Tchigorsky directly. His hand dropped to his side. No need to tell him that danger was in the air. It was the thick, still kind of night that goes with adventure.

"Something has happened?" Geoffrey asked.

"Something is going to happen unless we prevent it," Tchigorsky replied. "The enemy has been foiled three times lately and is getting uneasy. He begins to realize that he has to cope with somebody who understands the game. It is no use to work in this deadly mysterious fashion as long as certain people can read the danger signals and act upon them, and therefore it has been decided to fall back upon more vulgar methods. You are not afraid of danger?"

"Not in the least. Try me."

"The danger is great. You are dealing with some of the cleverest people on earth. If you are discovered you will be put away. Your courage will be tested to the utmost. Are you ready?"

Geoffrey hesitated but for a moment. His senses seemed to be braced and strengthened. He seemed to hear better all at once; his eyes penetrated farther into the gloom. There was a feeling of eagerness, of exultation upon him. He took Tchigorsky's lean claw and laid it upon his left wrist.

"Feel that," he said. "Is not my pulse steady? I am longing to go forward. Only give me a chance to find the truth."

Tchigorsky chuckled. This was the kind of grit he admired.

"You will do," he said. "And you will go alone on your expedition. You are acquainted with all the vaults and passages of the castle by this time; every inch of the ground is known to you. Give me your coat and shoes."

Geoffrey handed them over, getting a pair of rubber-soled shoes and a rough pea jacket in exchange. In the pocket of the latter he found a revolver.

"Now what am I to do?" he demanded.

"Stand here," Tchigorsky explained. "Presently you will see a figure or two, perhaps more. You will not understand what they are saying, but that makes no difference. You are to follow them, stick to them. If nothing happens by dawn you can afford to leave them to their own devices. If circumstances place you in dire peril, be brave, for help is not far off."

Geoffrey might have asked another question or two. But Tchigorsky turned away abruptly and was speedily lost in the darkness. And then followed for Geoffrey the most trying part of the business, waiting for the first sign of the foe.

Half an hour passed and still no sign. Had the affair miscarried and the miscreants got away in some other direction? Strain his ears as he would, Geoffrey could catch nothing. Then at length something soft and rustling seemed to be creeping along on the lawn on the other side of the hedge.

Geoffrey crept through the gate into the garden. Almost instantly he dropped on his face, for somebody carrying a lantern was softly creeping in his direction. It was the figure of a woman, a woman who had a black lace shawl so wrapped about her that in the feeble light it was impossible to make out her features. She paused and made a hissing sound between her teeth.

As if they had been evolved out of Geoffrey's inner consciousness, there appeared two men upon the lawn One was lying on his back, his head supported on the arm of his companion. They were Indian natives of some kind, but of what race precisely Geoffrey could not say. The prostrate man had an ugly cut across his forehead; it was the same man that Geoffrey had seen looking through the window.

A crafty, ugly, sinister face it was, full of cunning malignity. The eyes were dull, but the fires of hate were still in them. The woman stooped down and produced cool bandages soaked in some pungent liquid, which she proceeded to bind round the brows of the injured man. Even at his respectful distance Geoffrey could catch the odor of the bandages.

He watched the weird midnight scene with breathless interest. There was something creepy about the whole business. If these people had nothing to conceal, all this surgical work might have taken place indoor; they might have called assistance. Geoffrey tried to catch sight of the woman's features.

But that was impossible. Still, there was something familiar about her. Geoffrey felt quite sure that he had seen that graceful figure before. She stood up presently and Geoffrey no longer had any doubt.

It was Mrs. Mona May.

The injured man rose also. He staggered along on the arm of his companion and Geoffrey could with some difficulty see them enter the sitting room. He paused in some doubt as to his next move, but before he was called upon to decide, Mrs. May and the other native came out again.

Evidently they had left the injured man behind. Then they emerged into the road and started off rapidly toward the cliffs.

"Going some way by the pace they are walking," Geoffrey muttered, "and at the same time they must be back before daylight, or they would never have dared to leave that fellow at Jessop's. What a good thing I know the country."

Geoffrey followed at a respectful distance, his rubber shoes making no sound. For the time of year the night was intensely dark, which was in Geoffrey's favor. Also, with his close knowledge of the locality, he had no fear of making mistakes.

The couple were not more than fifty yards ahead of him. They had not the slightest idea they were being followed, seeing that they were talking earnestly and none too quietly in a language that was Greek to Geoffrey. Now and again he caught the low laugh that came from the woman's lips.

By and by the cliffs were reached, and here the two began to descend a path that would have been dangerous to unaccustomed feet even in the broad daylight. But the man seemed to know the way perfectly and the woman followed without hesitation. They came presently to the firm sand, fringed by the ebbing tide.

Then they turned to the right, pausing at length before a solid-looking expanse of cliff that stood right under Ravenspur Castle. One moment they loomed darkly against the brown rocks, the next minute they seemed to be swallowed up by the cliffs. They had entered the mouth of a cave.

Geoffrey followed still more cautiously. On and on they went, until at length they paused. Then the light from the lantern grew stronger. From behind a ledge of seaweed-clad granite Geoffrey watched them furtively. They were waiting for something—a signal, probably—before going farther.

The signal seemed to come at last, from where it was impossible for Geoffrey to judge, and then the advance was resumed. Presently they emerged into the deep below-tide level vault under the castle, where Geoffrey had seen Marion walking in her sleep.

Mrs. May turned to her companion and gave him some sharp command. She had lost all her levity and Geoffrey could see that her dark eyes were glowing. The native salaamed and laid his hand upon the lantern. The next instant the place was plunged into pitchy darkness. Five, ten minutes passed, and nothing was heard but the lap of the ebbing tide on the shore. Then a hand was gently laid on Geoffrey's arm.