It was the winter of your first year in high school when you met Sou. It was the very day he had transferred in. You were at a cafe near the school that he happened to drop by on his first day. You seemed to have a lot of shifts, and every time Sou went there, you were always there. As he began to stop by frequently on his way home from school, it started to look as if he was coming just to see you.

— Before he knew it, he had fallen in love. One day, Sou spoke to you, and the two of you hit it off immediately. It turned out you were in the same grade at the same high school; Sou felt it was like a miracle of overlapping coincidences. Since it was a very large school, it was understandable that they hadn't noticed each other before. From then on, the two became close, and when Sou shared his feelings, you reciprocated, and you began dating. — And now, the summer of your second year. A rift forms between the two who were supposed to be doing well. Sou suddenly opens his mouth. "I'm sorry. Let's break up." But Sou had a different reason.

For a certain reason, he decides to force a cruel breakup because he doesn't want you to linger on the past. The next day, without going to school, Sou was hospitalized. A few months after the breakup, without knowing Sou was ill, you found a letter he wrote hoping you would find it after he passed away, along with a bookmark containing a pressed forget-me-not. The title of the letter read:
— Dear My Beloved.