A clatter of hoofs sounded above the arroyo and the next instant several horsemen appeared. Without knowing just what he was doing Jimsy, who had a rifle in his hands, pulled the trigger. He was amazed to see the giant form of Red Bill totter and reel in the saddle, and fall with a crash to the ground. The next instant horror at the idea that he had killed the man seized on him. His hands shook so that he almost dropped the rifle.
But there was little time for reflection. The sight of their leader's downfall seemed to drive the other outlaws to frenzy. They poured a leaden hail into the arroyo that must have exterminated every living thing in it if they had not sought shelter behind a mighty mass of boulders.
Hardly had they crouched there in temporary safety, before, far above them, came a familiar sound. The giant droning of an enormous beetle was what it seemed to resemble most. But Jess and Jimsy recognized it instantly.
"An aeroplane!" shouted Jess.
"It's Peggy and Roy!" cried Jimsy the next instant. Looking upward against the blue was outlined the scarab-like form of the monoplane.
At the same moment a terrific trampling of horses' hoofs sounded above. Shots and shouts rang out in wild confusion.
"What can be happening?" gasped Jess. Even Aunt Sally, cowering in her tent, summoned courage to peek forth. The sight they saw was an inspiring one. Bud and his horse hunters were riding down the outlaws in every direction.
While this was going on, the aeroplane swung lower. From it there stepped as it alighted, not Roy and Peggy, but Peggy and a strange young man whom nobody recollected having seen before. Without a word he bounced from the chassis as the aeroplane struck the ground, and, revolver in hand, set off in hot pursuit of Bud and his men, who, from horse hunters, had become man hunters.
The outlaws, outnumbered and outridden, were fain to cry for quarter. With the exception of three who escaped, the whole band was rounded up and made prisoners. Red Bill, who proved to be only slightly wounded, was captured by Sam Kelly himself.
The presence of the horse hunters on the scene at the opportune moment was soon explained by Peggy, who spent a busy hour relating all that had occurred since they left the camp. Roy, she explained, was still at the hotel in Blue Creek, but mending rapidly. She and the detective had encountered the horse hunters as the aeroplane was on its return journey, and, guessing from the tall bandit's story that the camp in the arroyo must be besieged, they enlisted the services of Bud and his followers.