I was not expecting the emotional one-two ending; it was so good. The story is about a Yellowstone wolf pack's leaders, 21 (alpha male) and 42 (alpha female), and their lifelong bond. There is a lot that unfolds, all based on the careful observations of the author and many others over the course of the late 90s, early 00s. Beautiful storytelling that merges science objectivity and human compassion.