Then, so suddenly as to startle even Nicky, the focused rays ignited the powder: there was a dull “boop!” and a blinding glare.

Before the smoke had risen and began to spread Cliff whispered, “Now—make for the door!”

Holding the flashlight pointed at the boy until the latter cowered back against the man, Cliff led his chums to the door. He fumbled with the catch: the man made a move as if to grapple with him but Cliff threw the ray into his eyes and he flung up his arm, instinctive fear of something not understood overcoming his wit. Cliff unfastened the clumsy catch, the chums fled to the street and were off like young gazelles.

“They’ll find the lens!” Nicky panted.

“What do we care?” demanded Tom, “They won’t get us!”

Of course all plans had to be altered; the youths could not be left behind. They were glad that in trying to prevent the expedition the Indian had only made their part in it certain.

On a fine evening, with all the natives engaged, and with all supplies packed, and with their course through the mountains carefully determined, they went to sleep for the last time in a civilized hotel—if the mean accommodations of the place they had selected could be called “civilized.” Mr. Whitley’s Lima friend had not proved a very good adviser. However, bright and early the next clear, temperate day—for Cuzco was not in the hotter lowlands where tropical heat was fiercest—they began their real adventure.

Bill and Mr. Whitley were in advance: then came the natives, laden with quite heavy packs, under which they toiled along on an ever ascending slope, singing native chants and talking in their unintelligible jargon. Behind them came the Mystery Boys, also laden with packs containing personal things and articles they wished to protect from prying eyes.

“We’re on our way,” they told each other and felt like capering at the certainty that in trying to frustrate their plans the Indian had made it possible for them to go along.

Up in the hills a tall, well built Indian stood with several companions, watching the lower passes.