"Well, here goes, then!" cried Sandy.

Without waiting for his chum he sprang around the corner or the wall, his electric advanced, his automatic ready for instant use. As he turned the corner one foot caught on a loose rock and he half fell to the ground. As he did so, Tommy saw a hairy paw shoot out with vicious force and brush and scrape across the boy's shoulder.

Tommy heard the boy's coat ripping and tearing under the clutch of the great claws, and heard his chum utter a piercing scream as the wicked claws touched the flesh.

It seemed to Tommy that the figure of his chum, now lying prostrate on the floor of the cavern with the head extending outward, was being drawn away from him by the claw which still clung to the shoulder.

He raised his automatic to fire and pushed his searchlight forward. The bear's eyes closed for an instant under the strong finger of light, and the bullet caught him, exactly in the center of the forehead.

He dropped with a savage growl, scrambled, to his feet again and dashed toward Tommy, who fired shot after shot at the advancing animal, but apparently without avail. In a moment all three bears, doubtless excited by the smell of blood, sprang before the entrance to the little cave where Tommy stood. For the moment the animals paid no attention to Sandy, still, lying prostrate on the floor, blood oozing from the wounded shoulder. Tommy fired shot alter shot as the bears came on.

For the first time in his life Tommy realized that the next moment might be his last. He saw Sandy lying bleeding on the floor. He saw three savage, pain-maddened animals rushing upon him and worked the trigger of his automatic until the clip was spent. Then he hurled the useless weapon at the nearest animal and seizing Sandy by the feet, dragged him farther into the cavern.

"I guess it's all off now," he mused as the bears stood hesitating and apparently ready for a spring. "I wish we'd left a note for Will."

He heard the clatter of sharp claws on the rocky floor, saw the pig-like eyes of the animals shining red under the light, heard their spasmodic breathing, and was about to make a desperate rush forward when the outer cavern was flooded with a racing light which grew and grew as Tommy looked. Then he heard the sound of feet.

Next came a volley of shots, followed by the shouts of men and the call of a voice that he knew.