Konna Shousetsu, Kakanakereba Yokatta.

"Will you always be with me, next to me?"
"Yes. Always."
We made a promise when we were children. Since then, Tsumugi and I have always done everything together, and our relationship was supposed to be unchanging. But then...

"I want to fall in love. Can you write a story about it?"

Tsumugi, who was weak and in the hospital, asked me to write a novel about a romance between her and a boy I used to know.
Our relationship began to change from that single "request". What was Tsumugi really looking for in love and fiction?
A coming-of-age story spun between me, her, and him.

(Source: Gagaga Bunko, translated)