Kanzaki Aoi is a popular high school idol who is in a romantic relationship with her childhood friend and next-door neighbor, Kurusu Akito. They are constantly together, even walking to school together in the mornings. She admires and respects him, still recalling the time he saved her when they were younger. However, all their dreams of staying together shatter when Aoi is forced to engage in daily obscenities with the physical education teacher, Shoda. With each passing day, she realizes that she enjoys it more and more. Even after the powerless Akito discovers the truth, Aoi demonstrates to him just how much she desires Shoda instead.