Koukou Debut is a Japanese manga series written and illustrated by Kazune Kawahara. It follows the story of Haruna Nagashiro, a high school girl who wants to make a fresh start in her new school. Determined to become popular, she seeks the help of Yamato Natsukawa, a boy known for his charm and good looks, to teach her how to attract attention. As Haruna navigates the challenges of high school life, she learns about friendship, love, and self-acceptance. The series explores themes of personal growth and the complexities of teenage relationships, making it relatable to many readers.