Natsuki Enomoto is rehearsing her confession to Yuu Setoguchi while her younger siblings, Kotarou and Hina, struggle to express their own romantic feelings. Hina is smitten with her senior Koyuki Ayase after an awkward encounter in middle school, and soon realizes that this is her first experience with love. Hina decides to attend Sakuragaoka High School to be close to Koyuki and her brother Yuu, but the trio and their friends become entangled in each other's emotions. Hina's bold yet sensitive nature leads her to confess her feelings to Koyuki, while Kotarou is unsure of his love for Hina but is determined to make her happy. In Suki ni Naru Sono Shunkan wo.: Kokuhaku Jikkou linkai, Hina, Kotarou, and Koyuki navigate the challenges of first love and its impact on their relationships in high school.