――Why don't we try kissing?— —Just kidding, a virgin like you couldn't do it, right?—

Ibuki Kazami, a second-year high school student, has a sassy childhood friend. Her name is Airi Kamishiro, a girl rumored to be the prettiest in school, as cute as a blonde, blue-eyed doll. Ibuki and Airi were born on the same day, in the same place, and grew up like siblings. Perhaps because of that, Airi maintains her sassy attitude only towards Ibuki. One day, while they were bickering as usual, Airi challenged him with, "Why don't we try kissing?" With a sassy attitude, Airi provoked Ibuki, saying, "If you really don't feel any attraction to me... it should be easy, right?" "Just kidding, a virgin like you couldn't do it, could you?" Determined to finally 'show her' today, Ibuki replied, "Alright, then, let's do it." Airi stammered, "Huh? N-no, well, uh..." "What's wrong? Was that just bravado earlier?" "N-no way! Of course not!" And so, the two ended up kissing due to the turn of events.

However, when they actually kissed, Airi started to become flustered and affectionate more than expected...

This is the story of how these childhood friends, who are so close they constantly bicker and have unacknowledged mutual crushes (?), end up becoming a lovey-dovey couple.