Twenty-one-year-old August Green can recall every moment and emotion from the last decade of his life as though he were living it a second time. He remembers his sister Avery, and her perpetual excitement. He remembers her eyes, and how they gazed upon mundane balloons in a way that transformed them into heavenly objects. But mostly, August can remeber her disappearance, how it changed him, and the discovery two years later that would make the crack in his heart become a gaping crevice.