Once before Johnny had been made a fool of by horse thieves who plied their trade across the line. They had given him this very same airplane to keep him occupied and tempt him away from his duty while they stole Rolling R horses at their leisure. Wasn't this very money--thirty-two hundred dollars of it--going to pay for that bit of gullibility? Gulled into earning money to pay for an earlier piece of gross stupidity! "The prize--mark!" he branded himself. "By golly, they've got me helping 'em do worse than steal horses from the Rolling R, this time; putting something over on the government is their little stunt--and by golly, I fell for the bait just like I done the other time! _Huhn_!" Then he added a hopeful threat. "But they had me on the hip, that time--this time it's going to be different!" For the rest of that day he brooded, waiting for Cliff. What he would do he himself did not know, but he was absolutely determined that he would do something. CHAPTER TWENTY MARY V TAKES THE TRAIL On a Saturday afternoon Spring Street at Sixth is a busy street, as timid pedestrians and the traffic cop stationed there will testify. In times not so far distant the general public howled insistently for a subway, or an elevated railway--anything that would relieve the congestion and make the downtown district of Los Angeles a decently safe place to walk in. But subways and elevated railways cost money, and the money must come from the public which howls for these things. Gradually the public ceased to howl and turned its attention to dodging instead. For that reason Sixth and Spring remains a busy corner, especially at certain hours of the day. On a certain Saturday, months before the traffic cops grew tired of blowing whistles and took to revolving silently at stated intervals with outspread wings after the manner of certain mechanical toys, Mary V Selmer came from the Western Union's main office, and thanked heaven silently that her new roadster of the type called the Bear Cat was still standing at the curb where she had left it. Just beyond it on the left a stream of automobiles grazed by--but none so new and shiny, so altogether elegantly "sassy" as the Bear Cat. Mary V, when she stepped in and settled herself behind the steering wheel, matched the car, completed its elegant "sassiness," its general air of getting where it wanted to go, let the traffic be what it might and devil-take-the-fenders. Mary V was unhappy, but her unhappiness was somewhat mitigated by the Bear Cat and her new mole collar that made a soft, fur wall about her slim throat to her very ears and the tip of her saucy chin, and the perky hat--also elegantly "sassy"--turned up in front and down behind, and the new driving gauntlets, and the new coat that had made dad groan until he had seen Mary V inside it and changed the groan to a proud little chuckle of admiration.