Hinata and Mamiru, who attend the same girls' school, are close friends in the same class. However, their friendship gradually transforms after Mamiru writes a love letter to Hinata, evolving into a relationship where they become increasingly aware of their feelings for each other day by day. As time passes, their subtle connection deepens into something more than just friendship, and the thought of "I guess I really like you" blossoms within them, growing stronger with each passing moment...