KIRBY did not know what mountains they were. He did know that the Mannlicher bullets of eleven bad Mexicans were whining over his head and whizzing past the hoofs of his galloping, stolen horse. The shots were mingled with yelps which pretty well curdled his spine. In the circumstances, the unknown range of snow mountains towering blue and white beyond the arid, windy plateau, offering he could not tell what dangers, seemed a paradise. Looking at them, Kirby laughed harshly to himself.As he dug the heels of his aviator's boots into the stallion's flanks, the animal galloped even faster than before, and Kirby took hope. Then more bullets and more yelps made him think that his advantage might prove only temporary. Nevertheless, he laughed again, and as he became accustomed to the feel of a stallion under him, he even essayed a few pistol shots back at the pack of frantic, swarthy devils he had fooled.Three hours ago he had been eating a peaceful breakfast with his friend and commandant, Colonel Miguel de Castanar, in the sunlit patio of the commandant's hacienda. Castanar, chief of the air patrol for the district, had waxed enthusiastic over the suppression of last spring's revolutionists and the cowed state of up-country bandits. Captain Freddie Kirby, American instructor of flying to Mexican pilots in the making, had agreed with him and asked for one of the Wasps and three days' leave with which to go visiting in Laredo. The simple matter of a broken fuel line, a forced landing two hundred kilometers from nowhere, and the unlucky proximity of the not-so-cowed horsemen, were the things which had changed the day from what it had been to what it was.The one piece of good fortune which had befallen him since the bandits had surrounded the wrecked Wasp, looted it, and taken its lone pilot prisoner, was the break he was getting now. During the squadron's first halt to feed, he had knocked down his guards and made a bolt for the grazing stallion. So far, the attempt was proving worthwhile.