One day, I - a high schooler - found a paperback in the hospital. The "Infirmity Novel" was its title. It was a diary that Sakura Yamauchi, a classmate of mine, was writing in secret. Inside, it was written that due to her pancreatic disease, her days were numbered. And thus, I coincidentally went from "just a classmate" to a "secret-knowing classmate". It felt like I was being drawn to her, who was my polar opposite. However, the world presented the girl that was already suffering from an illness with an equally cruel reality...