When a dog flees without yelping he's a badly frightened creature. I instinctively started back towards the camp whence the beast had fled, and before I had taken a dozen steps Miss Barrison was beside me, carrying the dog in her arms.

"I've an idea," she said, under her breath.

"What?" I asked, keeping my eyes on the camp.

"It's this: I'll wager that we find those pies gone!"

"Pies gone?" I repeated, perplexed; "what makes you think—"

"They are gone!" she exclaimed. "Look!"

I gaped stupidly at the rough pine table where the pies had stood in three neat rows of four each. And then, in a moment, the purport of this robbery flashed upon my senses.

"The transparent creatures!" I gasped.

"Hush!" she whispered, clinging to the trembling dog in her arms.

I listened. I could hear nothing, see nothing, yet slowly I became convinced of the presence of something unseen—something in the forest close by, watching us out of invisible eyes.