Uka Ishimori, a very shy girl who was bullied in middle school and called “Stone” because she barely talked. Entering high school, she hopes to change and become more confident.
She meets Kai Miura, a cool and friendly boy with lemon-colored hair. Unlike others, Kai treats Uka kindly and encourages her to be herself. Inspired by his attitude, Uka slowly starts trying to step out of her comfort zone and face school life with a bit more courage.