tion on the part of his steed.

"Let's go, fellows!" cried Bud to his cousins, and, not waiting for the
permission of Mr. Merkel, the lads saddled their horses and started
after the foreman and his cowboys who had gotten a flying start.

"What do you imagine it is?" asked Nort as he rode between his brother
and cousin, while they urged their steeds on to catch up to those ahead
of them.

"Haven't any idea," answered Bud, glancing back to note that his father
and the visiting ranchmen had gone into the house. Probably Mr. Merkel
and the others knew the matter could safely be left to the cowboys.

Bud and his cousins rode fleet ponies, and they were more than at home
in their saddles, so it did not take them long to reach the bunch of
cowboys riding across the plains ahead of them, on the trail of the
mysterious night visitors.

"Any idea who they were, Slim?" asked Bud, guiding his horse alongside
that of the foreman.

"Not the least in the world. But they're up to no good or they
wouldn't have veered off at the first hail. There's something
suspicious in that."

"I should say so," agreed Nort.

"Couldn't be any sheep herders coming so soon, to turn their nibblers
on our land; could it?" Dick wanted to know. He spoke of "our land,"
for he and his brother owned a small ranch in partnership with Bud.

"No, I don't reckon it was the sheep herders themselves," said Slim,
"but it might be some of their bunch coming to size things up. The
government never made a worse mistake than to throw this Indian land
open to everybody. Them fellers at Washington should have barred the
sheep men!"

To hear Slim talk you would have imagined that he could go to
Washington and regulate matters all by himself. But if you understand
the feeling of western cattle men and horse men against sheep herders
it will make it easier to comprehend.

"Well, if any of 'em try to come to Happy Valley," said Bud, "they'll
wish they'd stayed out."

"That's right!" chimed in Nort and Dick.

Suddenly one of the cowboys on the outer fringe of the riding posse
uttered a low cry and exclaimed:

"There they are--off to the left!"

As he spoke the moon came out from behind ragged clouds and disclosed
two horsemen riding at full speed across the prairie.

"After 'em, fellows!" cried Slim, and he fired some shots in the air.

The boy ranchers put spurs to their steeds--not cruelly but with a
gentle touch to let the horses know a burst of