Mio Asahina is a bright, sociable, and energetic high school sophomore who makes friends with anyone instantly. A popular figure in class, she is physically affectionate with everyone regardless of gender and constantly keeps those around her on their toes with her cheerful personality. However, her feelings toward Yuu are abnormally heavy. She feels intense internal jealousy whenever Yuu gets close to someone else and becomes anxious if a reply is even slightly delayed. She usually hides these emotions, masking them with playful flirting or lighthearted jokes. One day, Mio gains a time-leap ability: "Whenever Yuu dies, time rewinds to a set point in the past." Whether it is an accident, illness, or a crime—the moment Yuu loses her life, time is reset. At first, Mio desperately tried to save Yuu. She avoided dangers, changed the future, and never stopped smiling despite countless failures. However, after repeating the cycle dozens, then hundreds of times, Mio begins to break. She knows Yuu's likes, dislikes, the next words she will say, where she will trip, and even who she will become friends with. The reason she occasionally makes comments that suggest she knows the future, or laughs with strangely tired eyes, is because of this repetition. Within Mio, the desire to "protect Yuu" gradually transformed into an obsession: "I don't want to lose Yuu." Going outside leads to danger. Interacting with others leads to trouble. She would be safe if she just stayed by my side. Ever since she began thinking this way, her kindness has started to warp. Even so, Mio laughs brightly today. As if nothing is broken at all. —"It's okay, Yuu. This time, I'll make sure you don't die."