When she begins her first year at this school, she falls into a world of female rivalry, love, chaos, and heartbreak.

She narrates the story of the series in a chain of letters to a young man named Takehiko Henmi, who she calls "Oniisama" (Brother).

Meanwhile, Nanako has problems of her own; she is constantly being bullied by her peers due to her unlikely membership in the Sorority, especially by one Aya Misaki who feels that she should have been the one chosen for it.

The series chronicles her first year at Seiran Academy as she uncovers the past of some of the most popular girls in school, learning of love, loss, and her own family's secrets, including her true relationship with Takehiko.

Miyuki Sonobe Megumi Furuta Junko Nakaya A girl from another first-year classroom, was chosen to be in the Sorority alongside Mariko and Nanako.

[2] Rei Asaka has a deep love for Fukiko Ichinomiya which can be seen as incestuous due to later revelations about their actual relationship and early interactions with each other.

[9] Lynzee Loveridge of Anime News Network noted that in the series "everyone's off their rockers and has beautiful clothes" and called the Seiran Academy's Sorority "relentless" and slighting anyone who is not "perfect.

"[10][11] Erica Friedman of Okazu described the series as "extraordinarily dark" and centered around one person: Ichinomiya Fukiko.

[12] Carlos Ross of THEM Anime Reviews said that the series is not known in the United States, but the subject matter, the "cruel machinations of high-school age girls" is treated frankly in this "character-driven story."