Adaptation of the eponymous manga by Satou Kukki (under the pen name of Vpan's Extasy).
Friends since childhood, Mizuki Suzumori and Souta Kazami have always had the chance to be able to find each other continuously in everyday life. Halfway through their last school year in high school, the duo exchange their love for each other. Six months passed. The end of the summer season is marked by graduation, and for the first time, it seems likely that the recent couple will take different paths. In order to guarantee the probability of going to the same university, Mizuki and Souta refrain from any romantic relationship so that they can focus on the exams. If Souta relies on his intellect to succeed, Mizuki prefers to bet on his assiduous athleticism. She ardently seeks the recommendation of the leader of the athletics club of which she is her best member. Another month passed without the duo seeing each other. It is then that Souta receives in his locker a strange DVD encouraging him to consult its contents ...