The story begins with Lady Celine of the Florbelk Viscount family being informed of her engagement to Julian, the eldest son of the Duke of Valdheim. Celine, a junior from a lower-ranking noble family with plain features, is bewildered by this union with Julian, a popular and handsome senior from a prestigious family. Their families' status disparity makes the engagement seem unusual, and Celine has never even spoken to Julian.
Upon arriving at the Duke's opulent mansion for the formal engagement, Celine is tasked with a "walk" in the garden with Julian for appearances. However, Julian is distant and cold when they are alone, a stark contrast to his demeanor in front of others. Their awkward stroll is interrupted by Mariebelle, Julian's cousin and a lady from a branch family of the Duke's. Mariebelle, with her seemingly sweet but calculating demeanor, immediately displays an intimate familiarity with Julian, intertwining her arm with his. Julian then casually reveals to Mariebelle that his engagement to Celine is merely a facade, a "white marriage" for appearances, and that his true affections lie with Mariebelle. This declaration deeply wounds Celine, who is left speechless and feeling like an outsider in her own engagement. Mariebelle then subtly taunts Celine, implying her foolishness for believing she could marry into such a high-ranking family. As Julian and Mariebelle walk away, Mariebelle feigns fear, accusing Celine of glaring at her. Julian immediately defends Mariebelle, sharply reprimanding Celine and reminding her of her lower status.
Celine later learns that Mariebelle is the illegitimate daughter of Julian's uncle, born from an affair. This complicated family history and the Duke's potential past affections for Mariebelle's mother have led to Mariebelle being raised alongside Julian, fostering an unusually close relationship. Celine's parents are distressed by her daughter's predicament, but the contract is binding, and breaking it would incur severe financial penalties. The contract itself is one-sided, lacking any provisions for Celine's compensation should the marriage dissolve, further cementing the Duke's manipulative intentions. Celine, however, resolves to not break down, understanding the need to protect her family.
The following days at school see Julian and Mariebelle openly displaying their affection, deliberately excluding Celine and making her feel like an unwanted presence. They arrive at school together in a conspicuous carriage, and during lunch, Mariebelle orchestrates an incident where Celine trips and falls, making it appear as though Celine is clumsy and unstable. Julian intervenes, but his words are more about managing appearances than genuine concern for Celine. Later, Julian confronts Celine, accusing her of trying to frame Mariebelle. Celine, however, begins to subtly play the victim, using their accusations and the unfairness of the situation to her advantage. She strategically feigns fear and distress, making it appear as though Julian and Mariebelle are bullying her.
This "victim act" begins to gain traction among the students, with whispers of Julian and Mariebelle mistreating Celine spreading. A young man named Lyca, a son of the Rendin Count family, witnesses an incident where Mariebelle throws a fan at Celine. Lyca retrieves the fan and later presents it as evidence to the Third Prince, who has been investigating rumors of mistreatment within the academy. The Prince, a just and responsible figure, summons Celine, Julian, and Mariebelle. He reveals he has obtained the engagement contract and points out its unfair, one-sided nature, questioning its legitimacy. Celine then recounts Julian's initial declaration of a "white marriage" and his harsh words, further solidifying the impression of her being mistreated. The Prince declares he will take charge of the engagement, promising an investigation and fair arbitration.
During the ensuing proceedings, Mariebelle, in a fit of rage, pushes Celine down the stairs. Lyca, who had been observing, intervenes and catches Celine, presenting the fan as evidence of Mariebelle's aggression. Another student corroborates Lyca's testimony, confirming Mariebelle's actions. The evidence and testimonies lead to Mariebelle's expulsion from the academy and the annulment of Celine's engagement to Julian. The Duke's family faces public scrutiny, and Julian relinquishes his claim as the next Duke. The incident also prompts a reform in royal law, prohibiting marriages between families with significant status differences without proper application and establishing a consultation service for contract disputes. Celine, having successfully navigated the treacherous social landscape, is now free from the engagement and is even proposed to by Lyca, whose genuine concern she recognizes. The story concludes with Celine accepting Lyca's proposal, looking forward to a future built on mutual respect and genuine affection.
