When she left him, she felt as if she knew a great deal about the end of her journey.

So she smiled and thanked the nice young man in that soft drawl that lingered pleasantly in his memory, and went over to another window and bought a ticket to Nogales.

She moved farther along to another window and secured a Pullman ticket which gave her lower five in car four for her comfort.
With an impulse of wanting to let her Uncle Carl know that she was not forgetting her mission, she sent him this laconic telegram: Have located Art.

Will bring him back with me.
JEAN.
After that, she went home and packed a suit-case and her six-shooter and belt.

She did not, after all, know just what might happen in Nogales, Mexico, but she meant to bring back Art Osgood if he were to be found alive; hence the six-shooter.
That evening she told Muriel that she was going to run away and have her vacation--her "vacation" hunting down and capturing a murderer who had taken refuge in the Mexican army!--and that she would write when she knew just where she would stop.