Ibuki Kazami, a second-year high school student, has a cheeky childhood friend named Airi Kamishiro.
Airi is said to be the prettiest girl in school, with her doll-like appearance of blonde hair and sapphire-blue eyes.
Ibuki and Airi were born on the same day and at the same place, and grew up together like siblings. As a result, Airi has always taken a cheeky attitude towards Ibuki.
One day, when they were quarreling as usual, Airi asks Ibuki, "Shall we try kissing?"
Ibuki responded, "Ha! Like a virgin like you could ever do it."
Airi provokes Ibuki with her cheeky attitude, saying, "If you don't feel any attraction to me, then I guess you have no chance, huh?"
Ibuki, determined to prove himself, decides to take up the challenge and answers, "Okay, let's do it."
But then he gets flustered and says, "Huh? N-no, wait..."
Airi asks, "What's wrong? Were you just bluffing earlier?" The two end up kissing unexpectedly.
However, when they actually kiss, Airi started to show more affection than expected...
This is a story about childhood friends who have a crush on each other and end up becoming a loving couple, even though they fought like cats and dogs.