It's Black Cloud who heads her off.

Black Cloud may not be the boss medicine man, but he's no fool, an' his eyes is like a wolf's eyes an' can see in the dark.

He guesses the new love which has stampeded Sunbright.
"Injuns is a mighty cur'ous outfit.

Now if Sunbright had succeeded in gettin' to the lodge of her new husband, the divorce between her an' Black Cloud would have been complete.

Moreover, if on the day followin' or at any time Black Cloud had found her thar, he wouldn't so much as have wagged a y'ear or batted a eye in recognition.