Description:

"On the last day of school, Mihane confesses to her senpai the long-term admiration she's had for her ever since they met, as well as tells her that she will try her best to enter Niji no Oka Girls' Academy next year, the school to which her Senpai is going to attend. Now, one year later, she's managed to pass the entrance exam to the prestigious school and is taking the bus to the school. Unfortunately, she takes the wrong bus, but encounters an interesting first-year girl, like her, that is also set to attend Niji no Oka Academy." -Manga Fox

Description:

Yumi Fukuzawa, who is basically a nobody and a first year student at Lillian Academy, a Catholic exclusive school for girls with a tradition that older girls take a younger girl as their little sister or "soeur", suddenly finds herself interacting with the members of the Yamayurikai and their soeurs when an innocent encounter leads Sachiko to impulsively ask Yumi to be her soeur. (Source: ANN)