After Natsuki Enomoto practices confessing her feelings to Yuu Setoguchi, their siblings Kotarou and Hina find themselves struggling to express their own love interests. Despite a rocky start with her senior Koyuki Ayase back in middle school, Hina is enchanted by his gentle demeanor and infectious grin, sparking her first experience with love. As Hina navigates these unfamiliar emotions, she decides to follow Yuu and Koyuki to Sakuragaoka High School, where the complexities of love weave a web around her and her companions. With a vibrant yet tender heart, Hina is determined to reveal her affection to the kind-hearted Koyuki while her brother Kotarou, unaware of his own feelings, is committed to ensuring Hina's happiness. 'Suki ni Naru Sono Shunkan wo.: Kokuhaku Jikkou linkai' chronicles the high school journey of Hina, Kotarou, and Koyuki, where their youthful romances cultivate new bonds but also strain existing ones.