At that instant Kris Kringle sprang to the opening of the cave.

"What does this mean?" he snapped.

"I don't know. Somebody knocked the axe out of my hand then shot at me."

The guide discovered the trouble right there. A bullet snipped his hat from his head; and, striking the ceiling of the cave-home, dropped to the floor with a dull clatter.

Kris Kringle ducked with amazing quickness. Crawling back into the cave, he reached for his own rifle and then sought the opening, taking good care not to expose himself to the fire of the unseen enemy.

Stacy, on his part, had lost no time in getting to a place of safety inside, though he was prudent enough to crawl instead of getting up and walking in.

"What does this mean? It can't be possible that anyone is deliberately shooting at us?" questioned Professor Zepplin in undisguised amazement.

"If you doubt it step outside," suggested Kris Kringle. "Master Stacy and myself know what they tried to do, don't we, lad?"

"We do."

The fat boy again swelled with importance.