"WE FLY SOUTH" Johnny did a great deal of thinking along the line suggested by old Sudden.

At first he thought merely how groundless was any suspicion that the airplane was in any way connected with the horse-stealing, except that it might justly be accused of contributing to his negligence.
Even so, Johnny could not see how one man could possibly protect the whole of Sinkhole range from thieves.

He could have been on his guard, could have noticed when the first horses were missing, and notified Sudden at once.

That, of course, was what had been expected of him.
But as to Tomaso and his oily brother, Johnny did not at first see any possible connection between them and his present trouble, save that they also had innocently contributed to his neglect.

But Sudden had told him to think about it, and the suggestion kept swinging his thoughts that way.