Flung face downward on a rough, uneven floor of rock by that jarring explosive crash, oblivion descended briefly upon Ruth Garnier. Brought to consciousness by a sharp, stinging pain in her left wrist, her first impression was that she had suddenly been stricken blind. Though her eyes were open, all around her was impenetrable blackness. Where was she? What had happened? She essayed to move her left hand, and moaned with pain. Using her right, she groped feebly about in the Stygian dark, her limp fingers coming in contact with what seemed to be solid rock, she braced her hand against it and slowly raised herself to a sitting posture.

Gradually she began to remember. First of all, that reverberating crash, as though a cannon had been fired off within a few feet of her. And before that? Now it was all coming back to her. She had gone to look for Blanche. Then she had seen the opening in the rocks. She had stepped into it, and found Blanche hiding there. She had tried to make Blanche come away. Then something terrible had happened. But where was Blanche now? How her head ached!

Still too greatly bewildered to reason out what had befallen her, Ruth passed her uninjured hand across her forehead. It encountered a good-sized lump near her right temple. The mere touching of it made her wince. Next she felt gingerly of her left wrist. Pluckily continuing to examine it, despite the pain it gave her, she decided that it was sprained but not broken. She thought that she must have landed heavily upon it when she fell forward. This much clear, her mind again reverted to Blanche. They had been facing each other when that dreadful thundering roar had begun. Now it seemed she was alone in the darkness unless—

In the grip of a new fear, Ruth dropped to her knees. Feeling her way with her sound hand she crawled slowly about in a little circle, widening it as she went. She knew now that she was still in the cave; that she was not blind. It was the light of outdoors, not her own eyesight which had been mysteriously blotted out in a moment’s time. The entrance to the cave was undoubtedly blocked by some huge object, hence the impenetrable blackness.

A low sigh of horror welled to her lips as her investigating fingers clutched a fold of wiry cloth. An instant and they had traveled upward to an arm and on up to a face. She had found Blanche. With a little sob, Ruth drew herself close to the motionless form and laid an ear against Blanche’s heart. It was still beating. Groping for one of her companion’s limp hands, she chafed it gently, calling out over and over again, “Blanche! Blanche! It’s Ruth! Oh, you must come to yourself soon!”

Hampered by her injured left hand, Ruth worked desperately over the unconscious girl with her right, now rubbing first one wrist then the other, now shaking her by the shoulders. A dash of cold water in her face, or a whiff of pungent smelling salts would have easily restored Blanche to consciousness. Ruth, however, had no remedy save that one willing hand, coupled with desperate determination.

After what seemed hours, in reality minutes, a long, shuddering sigh issued from Blanche’s lips. Ruth’s own heart almost skipped a beat when a faint voice mumbled, “Wh-at—oh-h—” and trailed off into silence. Creeping to Blanche’s head, Ruth raised it with difficulty, bracing it against her right shoulder. “It’s Ruth, Blanche. Don’t you know me?” she entreated.

“Y-es, Ruth.” Blanche’s voice was somewhat thick. Consciousness now rapidly returning, she asked faintly: “What’s the matter? I can’t see. It’s—so—dark. It’s night, isn’t it?”

“It’s night in here,” was the grim response. “It must be night outside, too. You—I—well, we are in the cave that we found. Do you remember about it?”

“What cave? No; I don’t remember it. There was something else; something terrible. I can’t think. The back of my head hurts.” Unsteadily, Blanche’s arm went up in a vain effort to locate her head.

“Lie still,” came the gentle command. “Don’t try to move or talk until you feel a little better.” Ruth had decided that, for the present, she would not try to inform Blanche of what had occurred. Time enough for that later on.

Crouching there in the darkness, the full gravity of their situation was borne upon her. Her brain now perfectly clear, she was of the conviction that some natural disturbance of the rocky ledge above was responsible for their imprisonment. For they were prisoners beyond a doubt. For how long? Ruth shuddered. Only too plainly one woeful fact confronted her. Both she and Blanche had slipped away from their friends without a word. In all probability, no one had seen them go. They alone had discovered the cave, and to their sorrow. She knew that long since, Miss Drexal must have started a hunt for them. Undoubtedly, the terrific rumble of falling rocks must have reached their ears. Yet how could they possibly guess that the two missing girls were prisoned behind them?

Ruth’s confidence in the Guardian was such that she knew Miss Drexal would insist on having every foot of the island explored in an effort to find them. And there was Blue Wolf, too. Recollection of the intrepid old Indian roused her to new hope. Had not the guide said that he knew the island. “You get lost, me find,” rang like a clarion in her ears. Perhaps he knew of the existence of the cave. Surely he must know.

Mere meditating on that one possible source of rescue consoled her not a little. It went far to alleviate the physical misery she was patiently enduring. Her head still ached dully, and the throbbing pain in her sprained wrist never stopped for an instant. Her whole body ached, too, from sitting so still, while Blanche’s head was a heavy weight against her shoulder. The latter had taken her advice, in that she had neither moved nor spoken since Ruth had last addressed her.

Alarmed by the thought that Blanche might have again relapsed into unconsciousness, Ruth was about to speak softly to her when a faint far-off sound set her aquiver. Was she dreaming or had she really heard it? Again it came, the distant ring of voices hallooing her name. Shifting her burden to the floor of the cave, Ruth stumbled to her feet and, moving quickly toward the blocked entrance, began to shout an answer at the top of her lungs.

“What are you doing?” was the querulous question. “What is it? Stop screaming. You hurt my head.”

Ruth paid no attention. Again and again, she repeated her frantic cries, Blanche expostulating with every shout. Though she listened desperately between calls, the welcome halloo she had just heard sounded only twice more, each time more faintly. It told her that her own voice had not been strong enough to penetrate the barrier that shut them in, and thus reach the ears of the faithful searchers. Overcome by the bitterness of her disappointment, Ruth dropped limply to the floor and sobbed aloud.

Her wild burst of tears did more toward bracing up Blanche than had all her previous ministrations.

“What is it, Ruth? Please tell me everything. I’m all right now.” Pulling herself together, Blanche crawled to where the other girl lay huddled, guided by the sound of her sobs. One of her hands strayed until it touched Ruth’s brown braids and rested there. “I know what’s happened to us. We’ve been caught in the cave. It didn’t come to me until you began to cry. Then I understood why you had shouted. Did you hear someone call, or were you just trying to get help?”

“I heard the girls. I know I heard them.” Ruth stopped crying and sat up. “I’m glad you are all right again, Blanche. It makes it easier for me to tell you how things are with us. You remember the way the rocks jutted out above this cave? Well, I thin............