When Yusami is reunited with her best friend, Sena, with a new school term, things get crazy! Sena's little sister is now in high school and can't wait to spend time with her sister! What Yusami didn't know was that Yusami's sister has a sister complex, and what's more is she has been in love with her sister for the longest. Yusami starts to figure out her feelings for her close friend, but will her feelings reach Sena?