Without another word he plunged into the pool.  Minute after minute passed, and he did not reappear.  Rod was conscious of a nervous chill creeping into his blood.  But Mukoki was chuckling confidently.

“Found heem!” he replied in response to the white youth’s inquiring look.

As he spoke Wabigoon came up out of the pool like a great fish.  Rod helped him upon the rocks.

“We’re two bright ones, we are, Muky!” he exclaimed, as soon as he gained his breath.  “Just behind the fall I ran up against the wall of rock we found when we were hunting for John Ball, stood on my feet, and—­” he swung his arms suggestively—­“there I was, head and shoulders out of water, looking into a hole as big as a house!”

“Dive easy!” warned the old pathfinder, turning to Rod.  “Bump head on rock—­swush!”

“We won’t have to dive,” continued Wabi.  “The water directly under the fall of the stream isn’t more than four feet deep.  If we wade into it from over there we can make it easy.”

Taking his waterproof bundle the young Indian slipped into the pool close up against the wall of rock that formed the foundation of the upper chasm and plunged straight into the tumbling cataract.  Mukoki followed close behind and preparing himself with a long breath Rod hurried into this new experience.  For a moment he was conscious of a smothering weight upon him and a thunderous roaring in his ears, and he was borne irresistibly down.  There was still air in his lungs when he found himself safely through the deluge so he knew that its passage had taken him only a brief but thrilling instant.  For a time he could see nothing.  Then he made out a dark form drawing itself up out of the water.  Beyond that there lay a chaos of midnight blackness, and he knew that his eyes were staring into the depths of a great cavern!

Gripping the edge of the rock ledge he dragged himself up as both Wabigoon and Mukoki had done, and found his feet upon a soft floor of sand.  Suddenly he felt a hand clutch his arm.  A half-shout, rising faintly above the wash of the cataract, sounded in his ear.

“Look!”

He wiped the water from his eyes and gazed ahead of him.  For a moment he saw nothing.  Then, so faintly that at first it appeared no larger than a star, he caught the faint glimmer of a light.  As he looked it became more and more distinct, and to his astonishment he saw that it was slowly rising, like a huge will-o’-the-wisp that had suddenly risen from the floor of the cavern to float off into the utter blackness of space above.  And even as he stared, gripping Wabi’s arm in his excitement, the strange light began to descend, and quickly disappeared!

The two boys saw Mukoki slip off into the gloom, and without questioning his motive they followed close behind.  As they progressed the sound of the fall came more and more faintly to their ears.  A blackness deeper than the gloom of the darkest night environed them, and the three now held to one another’s arms.  Rod understood why his companions lighted no torches.  Somewhere ahead of them was another light, carried by the mad hunter.  His blood thrilled with excitement.  Where would John Ball lead them?