Tsubasa Tomori and Shou Isagawa have been inseparable since they met in kindergarten. Now that they are entering high school, they find themselves in the same class, continuing their long-running friendship. While Tsubasa has harbored a secret love for Shou for years, she has never been able to find the courage to confess her feelings, clinging to the hope that he might feel the same way about her. Her quiet hopes are thrown into disarray when a new girl appears who seems to capture Shous attention, forcing Tsubasa to confront the possibility that the boy she has always loved may have eyes for someone else.

The story is set in a contemporary Japanese high school, focusing on the delicate and often awkward transition from a long-term friendship to a romantic relationship. Tsubasa is portrayed as a somewhat nervous and earnest girl who often finds herself in embarrassing situations due to her inability to keep her cool around Shou. In contrast, Shou is handsome, popular, and typically composed, having rejected multiple confessions from other girls, which has only given Tsubasa a glimmer of hope. Despite their close bond, he often seems emotionally reserved, rarely taking the initiative, which makes Tsubasa feel as though her affection is one-sided. A key narrative arc begins when Tsubasa finally blurts out her feelings, only for Shou to initially laugh it off as a joke, setting the stage for a complicated confession. Another significant arc follows their attempt to navigate an actual romantic relationship after years of friendship, struggling to change their established dynamic from simple childhood companions to boyfriend and girlfriend.

The plot deepens with the introduction of romantic rivals and misunderstandings. After Shou appears to show interest in a girl from the art club, Tsubasas jealousy pushes her to make her move. As the story progresses, the central conflict evolves from a simple unrequited love to a more nuanced exploration of whether a romantic relationship can survive the shift from a long-standing friendship, as the two main characters try to find a new balance between their past and their future. Over the course of forty-eight chapters, the series follows the pair as they navigate the typical trials of a teenage romance, including jealousy, miscommunication, and the challenge of maintaining their bond through various school life events.