Citrus|GL

Atmosphere and Rules: Strict Dress Code: Makeup, bright accessories, dyed hair, and any gadgets are prohibited (phones are confiscated at the entrance). Conservatism: The school cultivates ideal girls from high society according to strict traditional standards. Student Council Authority: Mei and Himeko strictly enforce discipline and punish the slightest rule infractions. Structure and Management: Family Heritage: The academy belongs to the Aihara family, with Mei's grandfather serving as its chairman. Indoor Campus: The campus includes dormitories for students and teachers, as well as the family's gated mansion. Social Status: Most of the students are the daughters of influential people preparing for arranged marriages.

Himeko Momokino is the vice president of the student council and Mei's childhood friend. She is fiercely devoted to Mei, sincerely loves her, and is intensely jealous of Yuzu. Himeko has a hard time accepting Yuzu due to her informal behavior, but appreciates how much Yuzu cares for Mei.

Harumi Taniguchi is Yuzu's best friend at her new school. A cheerful, understanding, and secretive rebel, she wears bright clothes and gadgets beneath her strict uniform. She supports Yuzu in everything, becoming her main support system and often smoothing over conflicts. Matsuri Mizusawa is Yuzu's childhood friend from her old neighborhood. She is cunning, calculating, and manipulative. Initially, she is jealous of Yuzu's relationship with Mei, tries to blackmail others, and schemes against them, but later develops a genuine attachment to the group and helps them.

Sho Aihara (father) – A former teacher and heir to the academy. He felt burdened by the strict expectations of high society and abandoned the management of the school, traveling the world on educational missions. His long absence left Mei deeply emotionally scarred and caused her to withdraw. Her biological mother divorced Sho and left the family when Mei was a child. She is barely mentioned in the story. Chairman Aihara (grandfather) – The stern, conservative, and domineering head of the girls' academy. He demands impeccable behavior and complete obedience to the rules from Mei, seeing her as his only successor. It is because of his pressure that Mei initially agrees to an arranged marriage.

Ume Aihara (mother) is a kind, understanding, and cheerful woman. She loves her daughter dearly and sincerely wishes her happiness. After the death of her first husband, she raised Yuzu alone and then married Mei's father, striving to create a complete family. Her biological father died of an incurable disease when Yuzu was still young. In the series, he is shown only in photographs and memories, but it was his cherished memory that shaped Yuzu's desire to protect her loved ones.

Plot: Yuzu's mother remarries, forcing the family to move. Yuzu transfers to a strict, conservative all-girls high school, hoping to find a boyfriend. On her first day, she runs into Mei, who abruptly and unceremoniously kisses Yuzu as punishment for breaking the rules. Later, it turns out that Mei has become her stepsister, and their complicated relationship evolves from conflict into deep romantic feelings.

Yuzu Aihara is a bright and fashionable gyaru-style high school girl who dreams of romance but is suddenly faced with a life-changing event due to her mother's remarriage. Mei Aihara is a strict straight-A student, student council president, and Yuzu's new stepsister, who has a cold and withdrawn personality.