(Updated again) Luo Yinshi, a senior high school girl, secretly works part-time as a light novel writer. She suffers from deep-sea phobia due to an accident at the beach in her childhood. She created a new work called "Under the Sea" based on the protagonist of a savior whom she met many years ago. She noticed that the campus swimmer Xu Yufeng, who was assigned to her class exactly after the college entrance examination, was very similar to the benefactor in her memory. In order to prove it, she began to try to get close to Xu Yufeng, but at the same time, her best friend Bian Xiaoyou suddenly and uncharacteristically made all kinds of advances to her. It's called an oral question challenge... Luo Yinshi originally planned to put the handwritten outline of "Under the Sea and the End of the World", which is a real confession letter to the person he yearns for, into Xu Yufeng's book to attract his attention, but unexpectedly, it was accidentally put into the exercise book of another boy, Ge Qizhang. After the confession letter was handed in without being noticed at all, things got out of hand...