Onii-sama e...

Nanako Misonoo enters Seiran Gakuen Girls High School and is assigned to Class B.

The nomination day has come. The nominees from Class B are Mariko Shinobu, Kaoru Orihara, and Nanako.

Nanako suffers from nasty harassment after being nominated to Sorority. On the verge of collapse because of the cruel bullying, Nanako thinks of declining the invitation to the party, which is to select the official members.

The day after the party, the finalized list of the new members is announced. Both Mariko and Nanako are listed. Nanako is surprised that she had been accepted even though she had not attended the party.

On the day of the entrance ceremony to Sorority, Nanako and fellow students are summoned for the preparation.

After Nanaoko is accepted in to Sorority, everyone at school is hostile to her, even Tomoko, her best friend. One day Nanako is unable to find her sports bag which she had brought for sure.

Persuaded by Miya-sama, Nanako decides to stay in Sorority. However, the unable to bear the continued harassment, she escapes to the clock tower.

Mariko feels uneasy about the restored friendship between Nanako and Tomoko. She invites Nanako to her birthday party. Although afraid of Mariko's eccentricity, she can't decline the invitatio

Nanako, who witnessed snippets of Mariko's insanity, realizes she cannot be open with her. One day, Kaoru suddenly collapses.

Kaoru worries about Mariko, who is growing more gaunt by the day. But Mariko is unable to accept her kindness, thinking that popular people like Kaoru cannot understand her loneliness.

Sorority members are attending the customary study meeting for the mid-term exam. Fukiko unusually invites Saint-Just and makes an appointment to meet under the elm tree in the courtyard at 5:00.

Kaoru visits Rei's home. Irritated at Saint-Just who is unable to shake her longing for Fukiko, Kaoru snatches from her arm a bracelet which symbolizes her obsession with Fukiko.

Although it is already past midnight, Nanako cares for Saint-Just, together with Kaoru. Nanako envies Kaoru and Saint-Just since she has never experienced such sympathy and friendship as exhibited by the two.

Saint-Just's words imply that she and Fukiko once tried to commit suicide together. Although the mid-term exam is near at hand, Nanako cannot stop thinking of Saint-Just.

Junko Nakaya, a first-year student in Class C, fails to rank in the top 50 in the mid-term exam, due to a fever. She is ordered by Miya-sama to voluntarily quit Sorority.

Kaoru participates in the first practice game since her comeback. Mariko, with a newfound adoration for Kaoru, tries to bring Tomoko and other students with no interest in basketball to cheer her on.

Kaoru leaves the hospital in just one day, and Mariko greets her with rapturous delight. Nanako is impressed by Mariko's honest display of love and envies her innocence.

Nanako happens to miss the bus stop for the school and ends up playing hooky with Saint-Just. Walking in a park, they run into Takehiko Henmi and his friend Takashi Ichinomiya.

Wondering how Saint-Just had interpreted her words, Nanako is uneasy. She becomes emotionally unstable, bursting into tears during class.

Nanako is invited by Takehiko to his university's festival and is delighted. On the other hand, Miya-sama is beside herself after finding out and summons Nanako to have tea with her the morning of the festival.

Nanako, Tomoko, and Mariko visit the university festival and are greeted by Takehiko and Takashi. Mariko is eager to protect Nanako and Tomoko from the immoral hands of men.

Fukiko invites Nanako and Mariko to her villa for the preparation of her birthday party. Late at night, Nanako happens to hear Miya-sama sobbing.

It is the 18th birthday of Miya-sama. One after another, gorgeous gifts are presented by Sorority members, and Nanako, who brought home-made cookies, is overwhelmed at the sight.

Saint-Just cannot understand what made Fukiko so angry. Then she is told a shocking story by Takashi.

Saint-Just finds out that Fukiko lost her pride because of Takehiko Henmi. She heads to Takehiko's home and confronts him.

Saint-Just feels both sad and angry at Fukiko, who had lost her pride because of love. Nanako heads off to her home in order to comfort her, but it is Fukiko who stands in her way.

Mariko reveals to Nanako and Tomoko that her parents are going to get divorced. Despite her calm and cool facade, Nanako detects the deep sorrow behind her demeanor.

Mariko disappears after the incident. Believing that Mariko's indiscretion had been caused by the divorce, her mother blames herself. Mariko returns home escorted by Takashi Ichinomiya.

Triggered by the Mariko incident, Nanako also leaves Sorority. Kaoru becomes acutely aware of the necessity of abolishing Sorority and consults with Saint-Just.

Kaoru begins a petition drive to abolish Sorority. Nanako brings in Tomoko and actively collects signatures. Even Saint-Just joins the campaign in order to protect Fukiko's pride in a real sense.

Fukiko stands by calmly, while other members are busy with the petition drive. Despite the dignified appearance, the members are increasingly worried.

The major members including Borgia quit the Sorority and sign the signature book of the petition drive. Fukiko, entirely isolated, visits Saint-Just and recalls the snowy beach where they once walked together.

The petition moved the student board at last, and it is decided to call an emergency meeting within a week. Saint-Just is relieved to finally see a dignified Fukiko, just as she was in her childhood.

Nanako gives up and starts heading home. At the entrance to the train station, she sees Tomoko in a deep fit of worry.

The somber funeral of Saint-Just is being held. Fukiko, holding back her sadness, tries to hold her head up high during the service.

Sorority is dissolved by Fukiko's decision. On her way back from the movies with Tomoko, Nanako sees Kaoru, who is breaking down crying at the spot where Saint-Just departed from this world.

Kaoru discloses her illness to Nanako, and tells her that is the reason why she can't continue the relationship with Takehiko. She also reveals that Takehiko is actually Nanako's real brother.

Takehiko is to study abroad in Germany, and he tries to persuade Kaoru to come along. But Kaoru is unable accept his love, considering his future and that she may only have five more years to live.

Takehiko and Kaoru decide to marry at last. Mariko and her mother rent an apartment. And Fukiko talks about Saint-Just and love....