Oniisama e...

When starting at a new school, Nanako is thrust into the world of female rivalry and love. She is chosen into the Sorority, giving her an enviable postition according to all the girls left out. However, since Nanako is not from a wealthy family, most girls find it unfair that she was choosen. Nanako is left to protect herself from wicked rumors and mean plots to make her leave the school. Along with her best friend since preschool, and new friends made along the way, she uncovers the past of some of the more popular girls in school and on her journey through highschool she learns of love, loss and her own family's secrets.

(Source: AnimeNewsNetwork)