"Ennis--quick!" shouted Campbell's voice across the cavern.

The Door dwindled away altogether; the great oval facet was completely black. The light was fast dying too.

The chief priest sprang madly toward Ennis, and as he did so, the hooded hordes of the Brotherhood recovered from their paralysis of horror and surged madly toward the dais.

"The Door is closed! Death to the blasphemers!" cried the chief priest as he plunged forward.

"Death to the blasphemers!" shrieked the crazed horde below.

Ennis' pistol roared and the chief priest went down. The light in the cavern died completely at that moment.

In the dark a torrent of bodies catapulted against Ennis, screaming vengeance. He struck out with his pistol-barrel in the mad melee, holding Ruth's stiff form close with his other hand. He heard the other drugged, helpless victims crushed down and trampled under foot by the surging horde of vengeance-mad members.

Clinging to the girl, Ennis fought like a madman through a darkness in which none could distinguish friend or foe, toward the door at the side from which Campbell had fired. He smashed down the pistol-barrel on all before him, as hands sought to grab him in the dark. He knew sickeningly that he was lost in the combat, with no sense of the direction of the door.

Then a voice roared loud across the wild din, "Ennis, this way! This way, Ennis!" yelled Inspector Campbell, again and again.

Ennis plunged through the whirl of unseen bodies in the direction of the detective's shouting voice. He smashed through, half dragging and half carrying the girl, until Campbell's voice was close ahead in the dark.

He fumbled at the rock wall, found the door opening, and then Campbell's hands grasped him to pull him inside.

Hands grabbed him from behind, striving to tear Ruth from him, to jerk him back. Voices shrieked for help.

Campbell's pistol blazed in the dark and the hands released their grip.

Ennis stumbled with the girl through the door into a dark tunnel. He heard Campbell slam a door shut, and heard a bar fall with a clang.

"Quick, for G.o.d's sake!" panted Campbell in the dark. "They'll follow us--we've got to get up through the tunnels to the water-cavern!"

They raced along the pitch-dark tunnel, Campbell now carrying the girl, Ennis reeling drunkenly along.

They heard a mounting roar behind them, and as they burst into the main tunnel, no longer lighted but dark like the others, they looked back and saw a flickering of light coming up the pa.s.sage.

"They're after us and they've got lights!" Campbell cried. "Hurry!"

It was nightmare, this mad flight on stumbling feet up through the dark tunnels where they could hear the sea booming close overhead, and could hear the wild pursuit behind.

Their feet slipped on the damp floor and they crashed into the walls of the tunnel at the turns. The pursuit was closer behind--as they started climbing the last pa.s.sages to the water-cavern, the torchlight behind showed them to their pursuers and wild yells came to their ears.

They had before them only the last ascent to the water-cavern when Ennis stumbled and went down. He swayed up a little, yelled to Campbell. "Go on--get Ruth out! I'll try to hold them back a moment!"

"No!" rasped Campbell. "There's another way--one that may mean the end for us too, but our only chance!"

The inspector thrust his hand into his pocket, s.n.a.t.c.hed out his big, old-fashioned gold watch.

He tore it from its chain, turned the stem of it twice around. Then he hurled it back down the tunnel with all his force.

"Quick--out of the tunnels now or we'll die right here!" he yelled.

They lunged forward, Campbell dragging both the girl and the exhausted Ennis, and emerged a moment later into the great water-cavern. It was now lit only by the searchlight of their waiting cutter.

As they emerged into the cavern, they were thrown flat on the rock ledge by a violent movement of it under them. An awful detonation and thunderous crashing of falling rock smote their ears.

Following that first tremendous crash, giant rumbling of collapsing rock shook the water-cavern.

"To the cutter!" Campbell cried. "That watch of mine was filled with the most concentrated high-explosive known, and it's blown up the tunnels.

Now it's touched off more collapses and all these caverns and pa.s.sages will fall in on us at any moment!"

The awful rumbling and crashing of collapsing rock ma.s.ses was deafening in their ears as they lurched toward the cutter. Great chunks of rock were falling from the cavern roof into the water.

Sturt, white-faced but asking no questions, had the motor of the cutter running, and helped them pull the unconscious girl aboard.

"Out of the tunnel at once!" Campbell ordered. "Full speed!"

They roared down the water-tunnel at crazy velocity, the searchlight beam stabbing ahead. The tide had reached flood and turned, increasing the speed with which they dashed through the tunnel.

Ma.s.ses of rock fell with loud splashes behind them, and all around them was still the ominous grinding of mighty weights of rock. The walls of the tunnel quivered repeatedly.

Sturt suddenly reversed the propellers, but in spite of his action the cutter smashed a moment later into a solid rock wall. It was a ma.s.s of rock forming an unbroken barrier across the water-tunnel, extending beneath the surface of the water.

"We're trapped!" cried Sturt. "A ma.s.s of the rock has settled here and blocked the tunnel."

"It can't be completely blocked!" Campbell exclaimed. "See, the tide still runs out beneath it. Our one chance is to swim out under the blocking ma.s.s of rock, before the whole cliff gives way!"

"But there's no telling how far the block may extend----" Sturt cried.

Then as Campbell and Ennis stripped off their coats and shoes, he followed their example. The rumble of grinding rock around them was now continuous and nerve-shattering.

Campbell helped Ennis lower Ruth's unconscious form into the water.

"Keep your hand over her nose and mouth!" cried the inspector. "Come on, now!"

Sturt went first, his face pale in the searchlight beam as he dived under the rock ma.s.s. The tidal current carried him out of sight in a moment.

Then, holding the girl between them, and with Ennis' hand covering her mouth and nostrils, the other two dived. Down through the cold waters they shot, and then the swift current was carrying them forward like a mill-race, their bodies b.u.mping and sc.r.a.ping against the rock ma.s.s overhead.

Ennis' lungs began to burn, his brain to reel, as they rushed on in the waters, still holding the girl tightly. They struck solid rock, a wall across their way. The current sucked them downward, to a small opening at the bottom. They wedged in it, struggled fiercely, then tore through it. They rose on the other side of it into pure air. They were in the darkness, floating in the tunnel beyond the block, the current carrying them swiftly onward.

The walls were shaking and roaring frightfully about them as they were borne round the turns of the tunnel. Then they saw ahead of them a circle of dim light, p.r.i.c.ked with white stars.

The current bore them out into that starlight, into the open sea. Before them in the water floated Sturt, and they swam with him out from the shaking, grinding cliffs.

The girl stirred a little in Ennis' grasp, and he saw in the starlight that her face was no longer dazed.

"Paul----" she muttered, clinging close to Ennis in the water.