Six Flowers (Rokka) and Rin are step-siblings who have grown up together. Rin has been secretly in love with his older sister for more than ten years, convinced that she only thinks of him as a younger brother. His quiet devotion is turned upside down when Rokka asks him to go on a "date practice" with her. Both are skilled at hiding their true feelings, and what unfolds is a painful, sweet dance of mutual unrequited love. The story alternates between their perspectives, revealing each character's hidden thoughts and the misunderstandings that pile up. From the first awkward outing, where they call each other by their first names and hold hands, to Christmas Eve and Valentine's Day, every ordinary milestone becomes charged with unspoken longing. As they try to maintain a sibling distance, the tension only grows. In later chapters, a group trip to the beach gives Rin's restrained possessiveness room to surface, further complicating their delicate balance. The series captures the agony of two people who are desperately in love but terrified to break the bond that ties them as family.