stars. Looking back up, Ennis saw the long, black mass of the house of Chandra Dass, resting on the black pier, ruddy light glowing from window-cracks. He collided with something and found that Campbell had led toward a little floating dock where some skiffs were moored. They scrambled up onto it from the water, and lay panting for a few moments.

Campbell had something in his hand, a thin, razor-edged steel blade several inches long. Its hilt was an ordinary leather shoe-heel.

The inspector turned up one of his feet and Ennis saw that the heel was missing from that shoe. Carefully Campbell slid the steel blade beneath the shoe-sole, the heel-hilt sliding into place and seeming merely the innocent heel of the shoe.

"So that's how you got loose down in the water!" Ennis exclaimed, and the inspector nodded briefly.

"That trick's done me good service before—even with your hands tied behind your back you can get out that knife and use it. It was touch and go, though, whether I could get it out and cut myself loose in the water in time enough to free you."

Ennis gripped the inspector's shoulder. "Campbell, Ruth is in there! By heaven, we've found her and now we can get her out!"

"Right!" said the officer grimly. "We'll go around to the front and in two minutes we'll be in there with my men."

They climbed dripping to their feet, and hastened from the little floating dock up onto the shore, through the darkness to the cobbled street.

The shabbily disguised men of Inspector Campbell were not now in front of Chandra Dass' café, but lurking in the shadows across the street. They came running toward Campbell and Ennis.

"All right, we're going in there," Campbell exclaimed in steely tones. "Get Chandra Dass, whatever you do, but see that his prisoners are not harmed."

He snapped a word and one of the men handed pistols to him and to Ennis. Then they leaped toward the door of the Hindoo's café, from which still streamed ruddy light and the babel of many voices.

A kick from Inspector Campbell sent the door flying inward, and they burst in with guns gleaming wickedly in the ruddy light. Ennis' face was a quivering mask of desperate resolve.

The motley patrons jumped up with yells of alarm at their entrance. The hand of a Malay waiter jerked and a thrown knife thudded into the wall beside them. Ennis yelled as he saw Chandra Dass, his dark face startled, leaping back with his servants through the black curtains.

He and Campbell drove through the squealing patrons toward the back. The Malay who had thrown the knife rushed to bar the way, another dagger uplifted. Campbell's gun coughed and the Malay reeled and stumbled. The inspector and Ennis threw themselves at the black curtains—and were dashed back.

They tore aside the black folds. A dull steel door had been lowered behind them, barring the way to the back rooms. Ennis beat crazily upon it with his pistol-butt, but it remained immovable.

"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 cockpit, 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 passes 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 Dass' 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