On her first day of university, Haruki had a fateful encounter with Sakura in the lecture hall. They were attracted to each other and lived together after graduation, but suddenly they had to part ways. Sakura had disappeared from this world. Five years have passed since then, and it is the fifth cherry blossom season. Haruki, who was still in a state of grief, happened to find a diary. It was the unfinished diary written by Sakura.