“Help! help! for God’s sake help!  Quick!  I am sinking . . .”

Nayland Smith grasped my arm furiously.

“We dare not move, Petrie—­we dare not move!” he breathed.  “It’s God’s justice—­visible for once.”

Then came the lightning; and—­ignoring a splitting crash behind us—­we both looked ahead, over the mire.

Just on the edge of the venomous green path, not thirty yards away, I saw the head and shoulders and upstretched, appealing arms of Van Roon.  Even as the lightning flickered and we saw him, he was gone; with one last, long, drawn-out cry, horribly like the mournful wail of a sea gull, he was gone!

That eerie light died, and in the instant before the sound of the thunder came shatteringly, we turned about . . . in time to see Cragmire Tower, a blacker silhouette against the night, topple and fall!  A red glow began to be perceptible above the building.  The thunder came booming through the caverns of space.  Nayland Smith lowered his wet face close to mine and shouted in my ear: 

“Kegan Van Roon never returned from China.  It was a trap.  Those were two creatures of Dr. Fu-Manchu . . .”

The thunder died away, hollowly, echoing over the distant sea . . .

“That light on the moor to-night?”

“You have not learned the Morse Code, Petrie.  It was a signal, and it read:—­S M I T H . . .  Sos.”

“Well?”

“I took the chance, as you know.  And it was Karamaneh!  She knew of the plot to bury us in the mire.  She had followed from London, but could do nothing until dusk.  God forgive me if I’ve misjudged her—­for we owe her our lives to-night.”

Flames were bursting up from the building beside the ruin of the ancient tower which had faced the storms of countless ages only to succumb at last.  The lightning literally had cloven it in twain.

“The mulatto? . . .”

Again the lightning flashed, and we saw the path and began to retrace our steps.  Nayland Smith turned to me; his face was very grim in that unearthly light, and his eyes shone like steel.

“I killed him, Petrie . . . as I meant to do.”

From out over Sedgemoor it came, cracking and rolling and booming toward us, swelling in volume to a stupendous climax, that awful laughter of Jove the destroyer of Cragmire Tower.

CHAPTER XXIV

STORY OF THE GABLES

In looking over my notes dealing with the second phase of Dr. Fu-Manchu’s activities in England, I find that one of the worst hours of my life was associated with the singular and seemingly inconsequent adventure of the fiery hand.  I shall deal with it in this place, begging you to bear with me if I seem to digress.

Inspector Weymouth called one morning, shortly after the Van Roon episode, and entered upon a surprising account of a visit to a house at Hampstead which enjoyed the sinister reputation of being uninhabitable.