Akiko Hayashi has soaring but strangely specific dreams: to make a successful manga debut while still in school, have her favorite actor star in its adaptation, and end up marrying him. However, she is far from having the motivation or skills to realize these hopes. When a friend introduces her to an unorthodox, backstreet art class taught by the strong-armed Kenzou Hidaka, called simply as "sensei," Akiko decides to enroll, expecting an easy ride and an automatic improvement in her art skills. To her chagrin, what she gets is something else entirely—a tough, demanding, and uncompromising teacher with absolutely no interest in manga.

But when Akiko takes up Sensei's challenge of an intense schedule, she comes to recognize how much he cares about his students and forms a close bond with him. With Sensei's guidance, Akiko learns what is necessary to become a successful mangaka as well as what it means to be an adult.