By the time Pembroke in pursuit had reached the turn and dared to peep around the corner of the wall, the Marquis was at the door of Dan's room. He stood there, ear bent close to the panel, intently listening.
Tom waited breathless. Not satisfied, Monsieur de Boisdhyver turned about and went into an adjoining chamber, the door of which stood open. Pembroke was about to advance, when the Marquis emerged again into the corridor, having left his lighted candle in the empty room. This manoeuvre, whatever advantage it had for the Marquis, was fortunate for Pembroke, for it left the end of the little hall, where he stood watching, in deep shadow. He could now step boldly from behind the concealing wall without fear of immediate detection.
Again the Marquis stood and listened at the door of Dan's room, then cautiously turned the knob. The door yielded and opened an inch or so. Monsieur de Boisdhyver put his ear to the crack. Dissatisfied with the absolute silence that must have met him, he pushed open the door a little further and thrust his head inside. In a moment he disappeared within.
Tom realized that the Marquis would soon discover the fact that the room was empty. He looked about quickly for a place of concealment that would command a view of all the halls. Fortunately the partition that divided the long corridor between the north and south wings was hung with heavy curtains. Deciding instantly, Pembroke slipped behind them, and ruthlessly slit an opening in the thick green stuff, through which he could peek out. He was just in time, as the Marquis came out of their bedroom and softly closed the door. He stood irresolute; then, with even greater caution, re-entered the room in which he had left his candle. To Tom's chagrin, the candle was suddenly extinguished and the Inn left in darkness.
For some moments, there was absolute silence. Then Tom could hear faintly,—or feel rather than hear—the Marquis cautiously finding his way back. Luckily, the old Frenchman was groping his way next the other wall. Pembroke slipped from behind the curtains and stole softly in pursuit. As he reached the south end of the corridor, he heard the latch of the Marquis's door click softly. Alarmed by discovering that they were not in bed, thought Tom, he had abandoned whatever purpose he had in mind for his midnight prowl.
After waiting a little and hearing no more, Tom went again to the window. The rain had begun now and the wind was blowing a gale. Suddenly Pembroke discerned a light shining from the window next the very one from which he was peering into the darkness,—the steady glow of a deep red light.
"Another signal!" he murmured; then waited to see if it would be answered by the House on the Dunes. Perhaps fifteen minutes passed, and then, suddenly, there gleamed through the rain and dark, a tiny bit of red flame, just where the House on the Dunes must be. A little later the red lamp on the Southern Cross performed a fantastic ascension to what Pembroke took to be the masthead.
The red light in the neighbouring window was extinguished. Almost instantly the red spark on the Dunes disappeared, and in a few moments the schooner's lamp began its descent. Simultaneously they glowed again and the ship's light danced upward; then the two red lights on shore vanished and the lamp on the Southern Cross sank to its proper place and stayed there.
Of one thing Tom was sure: The Marquis, the lady at the House on the Dunes, and the skipper of the schooner in the Cove, were in collusion. Of another thing he felt almost equally certain: the red light was a signal of danger, and the message of danger flashed across the night was the fact that he and Dan were not safe asleep in bed.
For a long time he watched, keen with excitement; listened patiently; started at every sound. But nothing more unusual did he hear that night than the roar of the wind, the dash of the brawling southeaster against the panes, and the groans of the old house, shaken by the storm. Toward morning he crept back to bed and fell instantly into a deep and dreamless sleep.