Haixing and Zaiwen were very good brothers at university, and they were both backbone members of the drama club, but they parted ways because they liked the same girl and never saw each other again. With the passage of time, Zaiwen, who runs a second-hand bookstore in Seoul, is nearly middle-aged. Instead of fading away, he visits his memories more and more frequently. The invasion of Su Dan, a mysterious girl, changed his life, prompting Zaiwen and Su Dan to go to Fukuoka, Japan to look for sea fish. In the trio of Zaiwen, Haifu and Su Dan once again, the past was opened little by little, but I don't know if it can really be resolved.