The butterfly effect: the idea that small, seemingly trivial events may ultimately result in something with much larger consequences. Instead of meeting Mondo as planned, Chihiro ends up talking to Byakuya... and reveals his secret. Then, they find a dead body in the locker rooms. (Chihiro didn't ask for everything that followed- he really didn't- but had no choice to go along with it. But maybe, just maybe he could even change some things, including himself...)
62 parts