Rascal Does Not Dream of a Lost Singer (light novel) by Hajime Kamoshida
Sakuta has now graduated from high school and is enjoying his new and peaceful life as a college student. One day, he bumps into the leader of the idol group Sweet Bullet, Uzuki Hirokawa. But somehow, she feels different from usual. Is the airhead able to read the room now?! However, no one notices this change besides Sakuta. Has Adolescence Syndrome affected Uzuki as well, or is it something else...?