The story begins with Souichi, a lonely high school student, lamenting his friend Sakazaki's increased unavailability due to his new girlfriend. Souichi himself desires a girlfriend and expresses this wish aloud on a hill. To his surprise, a woman's voice responds, offering to be his girlfriend. He turns to see Sora Kuroomiya, the beautiful and popular student council president of his school. Souichi is bewildered, as he has no prior acquaintance with her and cannot fathom why she would propose such a relationship.
Sora reveals she knows Souichi's name and explains her unusual proposition. She admits to never having dated before and wishes to experience a romantic relationship during her remaining year of high school. She specifically sought someone who hadn't confessed to her, desiring an equal footing in the relationship, free from the pressures of reciprocated affection. Souichi, though confused and initially believing it to be a joke, eventually accepts her offer, partly out of his desire for a girlfriend and partly due to an inexplicable feeling of wanting to help her. They agree to call each other by their first names, with Souichi using "Yozora-senpai" and Sora calling him "Souichi." Sora also lays down a strict rule against cheating, emphasizing the need for open communication if either develops feelings for someone else. She then surprisingly invites Souichi to join the student council, which he reluctantly agrees to, framing it as him voluntarily assisting her.
The next day, Souichi informs Sakazaki about his new relationship, who reacts with envy not at the beauty of his girlfriend, but at the ease with which Souichi found one. Souichi then meets Sora for lunch. He goes to her classroom to pick her up, causing a stir among her classmates. Sora, embarrassed by his direct approach, eventually introduces him as her boyfriend. This revelation causes a commotion, and Sora's friends begin questioning Souichi. They retreat to the student council room to avoid further attention. There, Souichi suggests they sit closer together to feel more like a couple, which Sora agrees to, admitting her inexperience in romantic matters. They discuss their lunches, with Souichi revealing his bento is mostly made of frozen foods, impressing the wealthy Sora.
During their lunch, Sora expresses her concerns about Souichi facing backlash from other students due to their relationship, especially from boys who might resent him for dating the school's "idol." She worries about him being targeted due to the perceived disparity in their popularity. Souichi reassures her that he can handle it and is willing to be a shield for her. He also expresses his desire to understand her better, feeling a lingering sense of mystery about her true feelings.
Later, Souichi and Sora go shopping. They discuss their preferences for food, with Sora revealing she rarely eats out but occasionally goes to sushi restaurants with her father. Souichi feels inadequate, realizing his financial limitations compared to her. To ease the situation, Sora suggests they go to a conveyor belt sushi restaurant, expressing a curiosity about the novelty of rotating sushi.
During their date at the aquarium, Souichi notices a hint of sadness in Sora's smile. He gently probes, and she reveals that she was reminded of her mother, who used to accompany her to the aquarium. This triggers a brief moment of vulnerability for Sora, who then expresses a desire to one day have a family of her own, hinting at a future where she might become a mother. Souichi feels a growing desire to understand her more deeply.
Their day continues at a shopping mall, where they decide to eat at a conveyor belt sushi restaurant. Souichi feels a bit self-conscious about his financial situation, but Sora reassures him by expressing interest in the restaurant. They also discuss their lack of strong food preferences, making it difficult to choose a restaurant.
The narrative highlights the developing relationship between Souichi and Sora, marked by Souichi's earnest efforts to be a good boyfriend and Sora's gradual opening up, revealing her inexperience and underlying complexities. The school community's reaction to their unusual pairing is also a significant element, with Souichi's bold declaration in Sora's classroom surprisingly earning him some respect.
