When Yusami reunites with her best friend Sena at the start of a new school term, things take an unexpected turn. Sena's younger sister, now in high school, eagerly anticipates spending time with her sibling. However, Yusami soon discovers that Sena's sister harbors a complex affection for her sister and has been in love with her for quite some time. As Yusami navigates her own feelings for her close friend, the question remains: will her sentiments reach Sena?