An amazing sight met his eyes.

Gatineau was stretched full length on his back. He was moving nervelessly, struggling feebly. Squatting over him was a tall, inexpressibly gaunt man. This fellow crouched over the detective’s chest with an almost stolid calm. His long, lean arms were stretched downward. His thin, knotty hands were about Gatineau’s neck. He was carefully and calmly throttling the life out of the little detective.

Clement caught one glimpse of the preoccupied face before it turned upon him. The face of this calmly murderous man was utterly transfigured with fear—fear that, somehow, did not interfere with the efficient labors of killing a man. Then the eyes turned to him as he charged forward. The fear in the fellow’s face leaped to an absolute panic at the recognition of Clement—and yet the fellow acted with an astounding calm.

He simply fell flat. He made no attempt at active resistance; he simply fell flat upon Gatineau. Then, as Clement jumped forward, he rolled, quick as lightning, towards him. It was unexpected. Clement in his stride could not check. His foot caught the lank, rolling body, and he pitched forward. As he fell, the other leaped to his feet, and jumped to the door. Clement had shut the door, and he caught at the handle. That gave Clement time to grab at him. As he fell, Clement twisted as he had often done on the football field. He did not try to recover, he let himself go, while trying to fall as near the door as possible. He succeeded enough to enable him to get his hand to the tall man’s ankle. He grabbed and held. He braced himself to resist.

The fellow was astonishing. He did not struggle. For a perceptible instant he stood there at the half-open door, staring down at the man who held his ankle. The look of devastating fear on his face was appalling. Clement had never seen any man so afraid. In that flash—it was no more than a single breath—he felt that the fellow was theirs—he was nerveless with fear. Then the lank man kicked him.

He kicked with his free foot coolly and deliberately—an astonishing kick when Clement recalled the sheer fright on the fellow’s face. So unexpected was it that Clement had only time to half-check the drive of the heavy boot with a quick-flung hand—and then his head rang and he saw a million stars.

After that, confusion. The lank man wrenched himself free and was running. Clement, dazed, tried to get up to go after him. He was knocked sideways by some one rushing by. It was only when he managed to get into the dark passage—that somehow seemed to be misty (but that was that fellow’s boot)—that he realized that the man who had bowled him over was Gatineau. He saw Gatineau running along the passage before him. Gatineau was groggy but determined. Rather groggy himself, he ran after Gatineau.

He had to trust to Gatineau. He couldn’t see the lean man, but Gatineau seemed to know. Gatineau went upstairs instead of down. Gatineau rushed across a roof landing instead of going through one of three doors, and flung himself headlong on to a fourth door. That burst wildly open under his charge, letting in a bewildering flash of daylight. They were on the roof. Then Gatineau was running across the leads, and Clement after him—and, yes, there was the lank man running ahead.

The lank man rushed to the edge of the roof, started back, looked round with his incredibly fearful look, then dodged at a right angle. Gatineau could not check in time to head him off. But Clement could. He cut across the fellow’s path, and, like a fox, the fellow tried to double again. He dodged round a stack, and found Gatineau ready for him, pivoted, and ran for the parapet. He scrambled on to the parapet, and stood swaying, staring about him for a loophole of escape. Between him and the next roof was a ten-foot alley, but the other roof was lower, and he seemed to think it was a chance. Clement did not; he yelled, “Stop that, you fool. You’ll kill yourself.”

It was too late. The fellow had braced himself, had leaped. He went through the air in a way that showed he was no jumper. He seemed to hang in the air for an eternity. Then his feet came down on the parapet on the opposite side. For a breathless moment he hung there, clawing wildly, as though seeking to grasp support from the very air; then his balance went, he sagged backwards, fell, went out of sight with an uncanny abruptness.