August was right.  Black Bolly broke her halter about midnight and escaped into the forest, hobbled as she was.  The Indian heard her first, and he awoke August, who aroused the others.

“Don’t make any noise,” he said, as Jack came up, throwing on his coat.  “There’s likely to be some fun here presently.  Bolly’s loose, broke her rope, and I think Silvermane is close.  Listen sharp now.”

The slight breeze favored them, the camp-fire was dead, and the night was clear and starlit.  They had not been quiet many moments when the shrill neigh of a mustang rang out.  The Naabs raised themselves and looked at one another in the starlight.

“Now what do you think of that?” whispered Billy.

“No more than I expected.  It was Bolly,” replied Dave.

“Bolly it was, confound her black hide!” added August.  “Now, boys, did she whistle for Silvermane, or to warn him, which?”

“No telling,” answered Billy.  “Let’s lie low, and take a chance on him coming close.  It proves one thing—­you can’t break a wild mare.  That spirit may sleep in her blood, maybe for years, but some time it’ll answer to—­”

“Shut up—­listen,” interrupted Dave.

Jack strained his hearing, yet caught no sound, except the distant yelp of a coyote.  Moments went by.

“There!” whispered Dave.

From the direction of the ridge came the faint rattling of stones.

“They’re coming,” put in Billy.

Presently sharp clicks preceded the rattles, and the sounds began to merge into a regular rhythmic tramp.  It softened at intervals, probably when the horses were under the cedars, and strengthened as they came out on the harder ground of the open.

“I see them,” whispered Dave.

A black, undulating line wound out of the cedars, a line of horses approaching with drooping heads, hurrying a little as they neared the spring.

“Twenty-odd, all blacks and bays,” said August, “and some of them are mustangs.  But where’s Silvermane?—­ hark!”

Out among the cedars rose the peculiar halting thump of a hobbled horse trying to cover ground, followed by snorts and crashings of brush and the pound of plunging hoofs.  The long black line stopped short and began to stamp.  Then into the starlit glade below moved two shadows, the first a great gray horse with snowy mane; the second, a small, shiny, black mustang.

“Silvermane and Bolly!” exclaimed August, “and now she’s broken her hobbles.”

The stallion, in the fulfilment of a conquest such as had made him king of the wild ranges, was magnificent in action.  Wheeling about her, neighing, and plunging, he arched his splendid neck and pushed his head against her.  His action was that of a master.  Suddenly Black Bolly snorted and whirled down the glade.  Silvermane whistled one blast of anger or terror and thundered after her.  They vanished in the gloom of the cedars, and the band of frightened horses and mustangs clattered after them.