Ruu Kurokiya, a fashionable kuro gyaru, is on the verge of flunking out of high school. In a bid to save her academic standing, the school assigns a private tutor: the stern and studious honor student Tadao Tadashi. However, their situation is more complicated than a simple student-teacher dynamic. Years earlier in elementary school, the roles were completely reversed; Ruu was the diligent, high-achieving student who helped Tadao, who was struggling, with his studies. After being separated during middle school, they are now reunited in high school with their positions swapped and with Ruu having transformed into a carefree gyaru.

Ruu is secretly thrilled to be reconnected with her childhood friend and harbors a crush on him. But rather than confess her feelings or focus on improving her grades, she becomes obsessed with a single goal: using her new gyaru charm to fluster Tadao and finally lead him around by the nose. Unfortunately for her, Tadao is incredibly serious and seemingly impervious to her seductive antics, maintaining a "take-it-serious" attitude that constantly thwarts her teasing. This clash between Ruu's "gyaru's pride" and Tadao's stubborn earnestness forms the core of their daily, chaotic study sessions.

The story takes place in and around their high school and homes, primarily during the tutoring sessions that Ruu continually derails with flirtatious distractions. As the narrative progresses, the cast expands to include their friends. Ruu is joined by her shy classmate Mashiro Yukiginu, who secretly draws a popular manga based on Ruu and Tadao's romantic dynamic. On Tadao's side, his honor student friend Ren Hamada enters the picture, nursing a secret crush on Mashiro.

Several key narrative arcs drive the story forward. An early arc focuses on Ruu's desperate need to pass her final tests, with the promise of a date hanging in the balance as motivation. A later arc shifts the setting to their private study sessions, which soon encounter a new obstacle when Ruu's overprotective mother becomes suspicious of her daughter spending so much alone time with a boy. The story builds toward major turning points, including a sleepover event that tests their relationship and ultimately leads to a confession. The manga concludes with their romance reaching its final resolution, as Ruu finally stakes everything on her gyaru pride to get a reaction from the boy she loves.