Aoi and Riku, who have been friends since they were five years old, are part of a band with other students at the university they attend. Riku is known as being unflappable and "perfect" to fellow band members. Rifts and misunderstandings in the band, Strobocorp, lead to a misfired performance on Aoi's birthday at a local festival, after which she has a tragic accident. She awakens to find herself re-living the prior week before the problems emerged, and Riku reveals that he can turn back time. He explains that he has been doing this for years, allowing him to perfect his apparent abilities. They admit to each other that their feelings go beyond friendship as they repeatedly relive the past.