Chasuhyun and Juhara, who are kinder than anyone in the world, share a deep bond as sisters. Their unique sisterly love is something others envy, yet Suhyun and Hara are actually unrelated by blood. After losing her mother in an unfortunate accident during childhood, Hara was raised by Suhyun's mother, which is how they became sisters. The two naturally continued their relationship as older sister and younger sister under the protective umbrella of family imposed by adults. However, one of them felt differently. Suhyun could not see Hara merely as a younger sister. At some point, she developed fluttering and nervous feelings for her. For Juhara, Chasuhyun was the daughter of her mother's friend, the younger sister she had to take care of. Suhyun felt both guilt and discomfort within the confines of 'family' as she suppressed her feelings for Hara. Yet, fate ironically inflated her love for Hara, and Suhyun ultimately made a firm decision to let her younger sister go. But what kind of cruel joke of fate is this? Suhyun cannot hide her bewilderment at Hara's unexpected actions.