Young writer Aihara Shin (Rior Mukai), who recently won the Newcomer Award, received an invitation from his hometown's alma mater, and reluctantly wanted to return to school to give a report speech.Not long after getting off the train, he met Senior Sister Shen Lin, who was regarded as a goddess at the time. The communication in the cafe reminded Asheng of an unforgettable story from his student days.15 years ago, Ah Sheng (played by Taro Takeuchi) had no sense of existence at all, while her senior sister Shin-roko (played by Ainaka Ishihashi) attracted much attention, and she was also surrounded by Miyazaki Shun (played by Asuka Kudo).No one expected that Miyazaki and Ah Sheng were childhood sweethearts playmates.Shun brother secretly dates a girl named Masae Yang (played by Hayami Akira) with his back. In order to hide his girlfriend, he asked Ah Sheng and Masae to pretend to be a boyfriend and girlfriend on campus.In order to repay Brother Shun, A Sheng reluctantly agreed, but he never thought that this lie of youth would make him unable to forget it for a long time...