Two classmates, "Hinata" and "Mamoru," who attend the same all-girls school, are close friends who share similar interests. However, their friendship takes an unexpected turn when Mamoru confesses her feelings through a love letter, leading them to become more aware of each other's emotions. As they navigate these new waters, their relationship evolves beyond mere friendship, and they begin to realize that they harbor deeper feelings for one another. The story unfolds as they grapple with their growing attraction and the complexities of their blossoming romance, ultimately culminating in a passionate encounter that solidifies their status as lovers.

同じ女子校に通う「ひなた」と「まみる」は、同じクラスの気の合うトモダチ。しかしトモダチ同士の関係は、まみるからひなたへの1通のラブレターをキッカケに徐々に変化し、日を追うごとに相手への想いを強くする「意識しあう関係」に発展。やがて2人の微妙な関係は、トモダチ以上の感情に変わっていき、互いの中で《やっぱり、君が好き》という想いが高まり、少しずつ深まっていく…。