Koshiro Saeki is a 27-year-old marriage consultant down on his luck with love as Shoko Akimoto, his lover of 2 years, dumped him because she found him to be too cold. While moping over his crisis on a train, he comes across a high school girl crying with a button in her hand. When the girl drops her wallet while getting off the train, Koshiro gets off to bring it back to her and she smiles upon observing the sight of cherry blossoms in the air. Later on, Koshiro is given tickets to an amusement park from one of his clients and encounters the same girl outside his company. Koshiro takes the girl with him to the amusement park and the two develop an attraction to one another while on a ferris wheel as both find themselves to be having their woes with love. When the two are about to leave the amusement park, Koshiro is shocked to discover that the schoolgirl is actually Nanoka Kohinata, his younger sister he had not seen in 15 years because of being separated from their parents' divorce.