Walking to school can be a chore for the average Japanese high school student, but for first-year Chio Miyamo, it's always an adventure. She is constantly running late as a result of her late-night gaming sessions, forcing her to devise new routes to get to Samejima Private Academy on time. Chio has to deal with street-blocking detours, overzealous kabaddi players, and befuddled motorcycle gang leaders on her many bizarre journeys to school. These minor setbacks, however, are no match for Chio, AKA the legendary assassin "Bloody Butterfly," who has received special ops training as a result of her extensive gaming obsession. Chio, along with her best friends Manana Nonomura and Yuki Hosokawa, will go to any length to avoid her school's harsh penalties for cheating.