A little girl possesses a constitution inherently different from ordinary people—her heartbeat is exceptionally intense, powerful enough to shake her entire surroundings. Thus, whenever she casually walks down the street, passersby cast sidelong glances at her. In the quiet of the night, some are even disturbed by the violent sound of her heartbeat, and neighbors have lodged angry protests one after another. Yet, she has no way to stop any of it, resorting only to wrapping herself tightly in a bedsheet. She faces everything in the world alone, spending her days gazing down from her window at the ordinary, trivial lives of people on the street, troubled by how her peculiarity sets her apart from the world. Only the little birds that land on her windowsill are willing to approach her, even pecking food from her hand. One day, after thoroughly cleansing herself, she leaps out of the window, wings sprouting from her back, and joins the flock of birds in flight.