At the top of the mountain in some of the clear, moonlit evenings, Mona sang in her marvelous voice to the others, and Mrs. Dot, with tears in eyes, said it was no wonder the simple red folk worshiped the girl. They were songs of the old frontier days, and hymns that had been taught her by Mrs. Sherley; and to these the girl had added some of the mythical verse of the Indians, for which she had improvised quaint and weird airs that lent rare enchantment to them, especially to the savages themselves. The lieutenant and his wife never appeared at the top of the butte until after the keen eyes of Mona had carefully swept the horizon and every part of the plain for signs of Indians. She did not wish to dispel any part of her power over these people of the plains, and wished that the departure of the couple should be as secret as if their lives depended upon it. In spite of the happy years the girl had spent here, the coming of this young couple had opened up new vistas which she had begun to try and understand. Their stories of the beautiful world beyond, with its love and its tears, awakened new emotions. The love of this girl called Dot, and near her own age, for her handsome warrior husband was a revelation to this physically marvelous flower of femininity. She began to question herself if in the world beyond the plains there was not such love in store for her. Oh, the mysteries and miracles of the tender emotions! How soft and insidious their grasp, yet how tenacious. In a few short weeks the life of this child of nature had been taught the pangs and aspirations of the world. With the coming of Lieutenant and Mrs. Avery, Mona had experienced her first desires for education--that something, acquired from books and teachers which controls the world. She never tired of the fascinating relation of college incidents by Dot, or of Lieutenant Avery’s laughable experiences in the great university. But how could she attain them? In this strange place “the world,” which, it seemed to her, was just beyond the skyline, she understood that everything was attained by money--how could she first obtain the money? Already Mona was spending sleepless nights, never known before, because of this, her first touch with civilization. As yet she had said nothing to Mrs. Sherley or her new-found friends, but she could not long hide her troubles. CHAPTER XXXVII. THE SCOUT ON A DIM TRAIL. At Fort Phil Kearney Buffalo Bill found orders based on the reports and recommendations of General Sheridan and other officers that he be assigned to the duty of learning the fate, if possible, of Lieutenant Avery and his bride.