Sasaki, a spirited blonde yankee, falls in love at first sight with his senior, Shiina, the school's most popular black-haired heartthrob. Despite Shiina being a notorious playboy who changes girlfriends frequently and claims to have no interest in boys, Sasaki remains undeterred, confessing his feelings repeatedly until his confessions number over 160. The story chronicles this persistent, one-sided pursuit where Sasaki's relentless affection clashes with Shiina's indifferent and dismissive attitude.

After countless rejections, Shiina and Sasaki finally become an official couple. However, their new relationship brings its own set of challenges. The formerly indifferent Shiina transforms into an overly affectionate boyfriend, while Sasaki grapples with new anxieties. The situation becomes more complicated with the arrival of a mysterious boy from the Kansai region who knows Shiina on a first-name basis, calling him "Rihito" and creating tension and jealousy.

As the story progresses through dates at the senior's house and an amusement park, the couple slowly grows closer, but their budding romance is tested by the appearance of a love rival named Nakamura. This new character, who clings to Sasaki and calls him by a friendly nickname, forces Shiina to confront new feelings of jealousy and possessiveness. The narrative concludes with this dramatic love triangle and the emotional climax of the main couple's journey.