At the center of Springadai High School, a tall, strikingly handsome girl named Mia Aida is known as the "Prince" and adored by female students for her cool, princely demeanor and commanding presence. Her childhood friend Rui Akai, by contrast, is a completely ordinary and unpopular boy who exists in her shadow as her self-described attendant. Every girl Rui has ever liked has ended up confessing to Mia instead, which frustrates him to no end.

One day, Rui asks Mia to teach him how to be more appealing to girls. Mia agrees and launches a series of "love training" sessions that quickly turn hands-on and physically close. The training begins with practice hugs and escalates to accidental kisses, shared bed scenarios, and increasingly intimate bodily contact. Mia, who secretly harbors feelings for Rui dating back to their elementary school days, uses these sessions as a pretext to close the distance between them. Rui, meanwhile, finds his composure tested as he struggles to suppress his growing romantic awareness of his childhood friend.

The story unfolds primarily on the school grounds and at the characters' homes. Mia's princely image hides a softer, vulnerable side: she is afraid of horror, eats enormous amounts of food, and becomes clumsy and puppy-like when flustered around Rui. Rui, despite his ordinary appearance, is academically top of his year and possesses a gentle, reliable nature.

The narrative advances through several major arcs. Early chapters focus on establishing the love training routine and the accidental kiss event, which shakes both characters. A close friend, Tarou Saikawa, becomes Rui's confidant and provides comic relief with his exaggerated reactions. The sharp-eyed Shizuku Kurosu joins the cast as an observer who quickly sees through the act and begins probing the duo's real relationship. Volume 4 introduces Rui's older sister Yuzuki, a possessive brother-complex character who returns home upon learning Rui is unwell and immediately clashes with Mia. A summer study camp follows, featuring swimsuit episodes, overnight tensions, and Yuzuki's interference, which forces Mia to confront her true intentions more openly. By volume 5, the new school term begins with Rui looking after a sick classmate named Kazuma, Mia accelerating her self-acknowledged "offense," and Shizuku beginning to act on a change of heart after the summer break.

Throughout these developments, the core dynamic remains the push-and-pull between Mia's aggressive, prince-like advances and Rui's flustered, reluctant-yet-responding resistance, all while both characters navigate the blurred boundary between childhood friendship and romantic love.