Kou Mabuchi is confessed to one day by a girl who has long held feelings for him. However, at that time, Kou was carrying the grief of losing his mother and had no room in his heart to love someone. "Sorry. I can't date anyone right now." He tells her this and rejects her feelings. Afterward, Kou tries to go on as if nothing happened, but he begins to notice that the girl no longer smiles like she used to and has started to distance herself from him. As they spend their school life together, he gradually becomes attracted to her kindness and earnest feelings, and he begins to regret it, thinking, "Back then, I didn't actually want to turn you down." However, this time, she is the one trying to move forward, and the distance between the two does not close easily. Despite repeated misunderstandings, Kou faces his true feelings and finally confesses his feelings himself, saying, "This time, I'll be the one to say it. I love you." The two then confirm each other's feelings and begin a new romance.

Touma Kikuchi is a popular boy who is bright, social, and can get along with anyone immediately. He is a mood maker who always entertains those around him with a smile, but he also has a kind personality, watching people's feelings closely and subtly reaching out to those in trouble. After meeting Futaba, he is drawn to her honesty and how hard she tries, and he begins to convey his feelings to her directly. Even knowing that Futaba cannot forget Kou Mabuchi, he doesn't give up, repeatedly telling her, "It's because I like you, Futaba," and continuing to make an effort to make her smile. Touma is very sincere regarding romance and is the type of person who puts the other person's happiness first. Even if he knows his feelings aren't reaching her, he doesn't try to force her to look his way, and he continues to cherish Futaba until the end. Because of this, he has become a character supported by readers who say he is "too kind" and "I want him to be happy." In the story, he is depicted as another important romantic interest who supports Futaba with a kindness and straightforward affection different from Kou Mabuchi's.

Yuri Makita is Futaba's classmate and one of her best friends. She has a quiet and reserved personality, but she is a very kind and caring girl who values the feelings of those around her. While she has a side that tends to go along with others too much, she gradually grows to express her own feelings without hiding them. At the start of high school, she struggled with making friends, but meeting Futaba allowed her to slowly gain confidence in herself. She and Futaba become important best friends who support each other and consult one another about troubles in love and school life. In romance, there is a period where she holds feelings for Kou Mabuchi, but she doesn't prioritize only her own feelings; she also values her relationship with Futaba and their other friends. Yuri, who possesses both kindness and honesty, shows the importance of friendship within the story.

Shuko Murao is Futaba's classmate and one of her best friends. She has a calm, mature atmosphere and a cool personality that doesn't show much emotion. However, she is actually caring toward her peers and is a considerate person who subtly supports friends in trouble. In romance, she harbors feelings for their teacher, Mr. Tanaka. While understanding that this love will not easily come true, she has the strength to remain honest with her own feelings. Her figure, trying to move forward despite her worries, has a great influence on Futaba and the others. She is bound by a deep friendship with Futaba and Yuri, and they are important comrades who support each other not only in romance but in school life as well.

Yoichi Tanaka is Kou Mabuchi's older brother and a high school teacher. He has a gentle and kind personality, sincerely valuing each and every student, and is trusted by the student body.

Yui Narumi is an acquaintance from the time Kou Mabuchi lived in Nagasaki, a girl with a bright and honest personality. She can treat anyone with kindness, and her friendly smile is her charm. She is one of the few people who knows the period when Kou lost his mother and spent painful days, and she has supported Kou since then. After reuniting, she continues to care about Kou and naturally acts close to him, which causes Futaba to feel confusion and jealousy. Yui has no ill intent and simply treats Kou as someone precious to her, but her presence becomes the catalyst that significantly shifts the relationship between Futaba and Kou. In the story, she is depicted as a person who knows Kou's past and as an important character who gives Futaba the chance to face her own true feelings.