Max Brand 
Thunder Moon and the Sky People [EPUB ebook] 

The big man at the window, as though fascinated by the flood of light within the room, remained for a long time staring. Finally he turned, and instantly he grappled with the smaller shadow behind him.
“It is I!” whispered the Cheyenne hastily. “It is Standing Antelope. Take your hand from my throat, Thunder Moon!”
He was free, and the two slipped silently through the garden, through the hedges, and back into the adjoining woods where they had left their four horses.
“I, also, have seen, ” said the boy.
“What?” asked the other.
“I have seen the reason that brought you from the Suhtai and made you travel all these moons into the land of the white men. I have seen his face!”
“You have seen him? Then who is he, Standing Antelope?”