Ishimori Uka is very shy and has trouble making friends. When she was in middle school, the other students teased her by calling her "rock." Around that time, she met Miura Kai, who had lemon-colored hair. Thanks to him, she ended up attending the same high school. Uka now wants to overcome her shyness and make friends. Kai is a popular student at the school, but he doesn’t talk much and doesn’t seem interested in others. He doesn’t know why, but he cares about Uka.