The story begins with Merusha Arnol, a noblewoman and engaged to Sebastian Smith, being confronted by him in the academy hallway. Sebastian is furious, accusing Merusha of harassing Lunna Wellboth, a petite woman clinging to his arm. Merusha, however, claims she was merely pointing out Lunna's uniform smelled. Sebastian dismisses Merusha's behavior, comforting Lunna and leading her away. Once alone, Merusha reveals her aggressive persona is an act, forced upon her by Lunna herself.
Merusha retreats to a quiet temple on the academy grounds, her sanctuary where she finds solace in petting a familiar black-spotted cat. She explains that two years prior, Lunna, a baron's daughter who transferred mid-year, began seducing Sebastian. Despite Sebastian's growing affection for Lunna, Merusha initially tried to rationalize it as a youthful infatuation. However, Lunna soon confronted Merusha, demanding Sebastian be "given" to her. When Merusha refused, Lunna revealed her manipulative nature. Lunna threatened Merusha's beloved cat, demonstrating her fire magic and forcing Merusha into a role of a villainess, while Lunna would play the innocent heroine. Merusha, fearing for her cat and bound by academy rules that prevent direct family intervention, reluctantly agreed to Lunna's scheme.
The narrative then jumps forward ten days, depicting Merusha executing a staged incident in the cafeteria where she knocks over Lunna's lunch, soiling her uniform. Merusha delivers her lines with forced theatricality, while Sebastian intervenes to defend Lunna. Merusha feels a pang of sadness seeing Sebastian use a handkerchief she gifted him. She seeks solace at the temple, confessing her actions to the goddess and confiding in the cat.
Another ten days pass, and Merusha is forced to push Lunna into a pond in the academy gardens. This time, an unexpected intervention occurs: the black-spotted cat, revealed to be the young priest Shisforlt Segrista in disguise, attacks Sebastian, causing him to fall into the pond as well. Merusha flees, worried about the cat's safety. Later, she learns from Shisforlt that he was protecting her and the cat, and that Lunna's threats were serious.
As graduation approaches, Lunna issues Merusha a high-difficulty "instruction" to push her down the stairs, threatening the cat if Merusha fails. Merusha, unable to go through with it, abandons the plan. At the graduation party, Sebastian publicly breaks his engagement with Merusha to marry Lunna, who is dressed in a white gown resembling a wedding dress. However, Shisforlt intervenes, revealing Lunna's manipulative schemes and threats against the cat, exposing her as a fraud. He then proposes to Merusha, confessing he has loved her for five years. The story concludes with Merusha accepting Shisforlt's proposal, their marriage, and the eventual dissolution of Sebastian and Lunna's union due to public scandal. Merusha finds happiness with Shisforlt and her beloved cats, while Sebastian and Lunna face social ruin.
