"No use--we can't break that down!" yelled Campbell, over the uproar.

"Outside, and around to the other end of the building!"

They burst back out through that mad-house, into the dark of the street.

They started along the side of the pier toward the river-end, edging forward on a narrow ledge but inches wide. As they reached the back of the building, Ennis shouted and pointed to dark figures at the end of the pier. There were two of them, lowering shapeless, wrapped forms over the end of the pier.

"There they are!" he cried. "They've got their prisoners out there with them."

Campbell's pistol leveled, but Ennis swiftly struck it up. "No, you might hit Ruth."

He and the inspector bounded forward along the pier. Fire streaked from the dark ahead and bullets thumped the rotting boards around them.

Suddenly the loud roar of an accelerated motor drowned out all other sounds. It came from the river at the pier's end.

Campbell and Ennis reached the end in time to see a long, powerful, gray motor-boat dash out into the black obscurity of the river, and roar eastward with gathering speed.

"There they go--they're getting away!" cried the agonized young American.

Inspector Campbell cupped his hands and shouted out into the darkness, "River police, ahoy! Ahoy there!"

He rasped to Ennis. "The river police were to have a cutter here tonight. We can still catch them."

With swiftly rising roar of speeded motors, a big cutter drove in from the darkness. Its searchlight snapped on, bathing the two men on the pier in a blinding glare.

"Ahoy, there!" called a stentorian voice over the roar of the motors.

"Is that Inspector Campbell?"

"Yes. Come alongside," yelled the inspector, and as the big cutter shot close to the end of the pier, its reversing propellers churning the dark water to foam, Ennis and Campbell leaped.

They landed amid unseen men in the c.o.c.kpit, and as he scrambled to his feet the inspector cried, "Follow that boat that just went down-river.

But no shooting!"

With thunderous drumfire from its exhausts, the cutter jerked forward so rapidly that it almost threw them from their feet again. It shot out onto the bosom of the dark river that flowed like a black sea between the banks of scattered lights that were London.

The moving lights of yachts and barges coming up-river could be seen gliding in that darkness. The captain of the cutter barked an order and one of his three men, the one crouched at the searchlight, switched its powerful beam out over the waters ahead.

In a moment it picked up a distant gray spot racing eastward on the black river, leaving a white trail of foam.

"There she is!" bawled the man at the searchlight. "She's running without lights!"

"Keep her in the searchlight," ordered the captain. "Sound our siren, and give the cutter her head."

Swaying, rocking, the cutter roared on through the darkness on the trail of that distant fleeing speck. As they raced down Blackwall Reach, the distance between the two craft had already begun to lessen.

"We're overtaking him!" cried Campbell, clutching a stanchion and peering ahead against the rush of wind and spray. "He must be making for whatever spot it is in England that is the center of the Brotherhood of the Door--but he'll never reach it."

"He said that within a few hours Ruth would go with the others through the Door!" cried Ennis, clinging beside him. "Campbell, we mustn't let them get away now!"

Pursuers and pursued flashed on down the dark, broadening river, through mazes of shipping, the cutter hanging doggedly to the motor-boat's trail. The lights of London had dropped behind and those of Tilbury now gleamed away on their left.

Bigger, stronger waves now tossed and pounded the cutter as it raced out of the river mouth toward the heaving black expanse of the sea. The Kent coast was a black blur on their right; the gray motor-boat followed it closely, grazing almost beneath the Sheerness lights.

"He's heading to round North Foreland and follow the coast south to Ramsgate or Dover," the cutter captain cried to Campbell. "But we'll catch him before he pa.s.ses Margate."

The quarry was now but a quarter-mile ahead. Steadily as they roared onward the gap narrowed, until in the glare of the searchlight they could make out every detail of the powerful gray motor-boat plunging through the tossing black waves.

They saw Chandra Da.s.s' dark face turn and look back at them, and the cutter captain raised his speaking-trumpet to his lips and shouted over the roar of motors and dash of waves.

"Stand by or we'll fire at you!"

"He won't obey," muttered Campbell between his teeth. "He knows we daren't fire with the girl in the boat."

"Yes, blast him!" exclaimed the captain. "But we'll have him in a few minutes, anyway."

The thundering chase had brought them into sight of the lights of Margate on the dark coast to their right. Now only a few hundred feet of black water separated them from the fleeing craft.

Ennis and the inspector, gripping the stanchions of the rushing cutter, saw a white figure suddenly stand erect in the boat ahead and wave its arms to them. The gray motor-boat slowed.

"It's Chandra Da.s.s and he's signaling that he's giving up!" Ennis cried.

"He's stopping!"

"By heavens, he is!" Campbell explained. "Drive alongside him, and we'll soon have the irons on him."

The cutter, its own motors hastily throttled down, shot through the water toward the slowing gray craft. Ennis saw Chandra Da.s.s standing erect, awaiting their coming, he and the two Malays beside him holding their hands in the air. He saw a half-dozen or more white-wrapped forms in the bottom of the boat, lying motionless.

"There are their prisoners!" he cried. "Bring the boat closer so we can jump in!"

He and Campbell, their pistols out, hunched to jump as the cutter drove closer to the gray motor-boat. The sides of the two craft b.u.mped, the motors of both idling noisily. Then before Ennis and Campbell could jump into the motor-boat, things happened with cinema-like rapidity. Two of the still white forms at the bottom of the motor-boat leaped up and like suddenly uncoiled springs shot through the air into the cutter. They were two other Malays, their dark faces flaming with fanatic light, keen daggers glinting in their upraised hands.

"'Ware a trick!" yelled Campbell. His gun barked, but the bullet missed and a dagger slit his sleeve.

The Malays, with wild, screeching yells, were laying about them with their daggers in the cutter, insanely.

"G.o.d in heaven, they're running amok!" choked the cutter captain.

His slashed neck spurting blood and his face livid, he fell. One of his men slumped coughing beside him, another victim of the crazy daggers.

_3. Up the Water-Tunnel_

The man at the searchlight sprang for the maddened Malays, tugging at his pistol as he jumped. Before he got the weapon out, a dagger slashed his jugular and he went down gurgling in death. One of the Malays meanwhile had knocked Inspector Campbell from his feet, his knife-hand swooping down, his eyes blazing.

Ennis' gun roared and the bullet hit the Malay between the eyes. But as he slumped limply, the other fanatic was upon Ennis from the side.

Before Ennis could whirl to meet him, the attacker's knife grazed down past his cheek like a brand of living fire. He was borne backward by the rush, felt the hot breath of the crazed Malay in his face, the dagger-point at his throat.