Olivia, a seventeen-year-old daughter of the ruined Ashel trading company, finds herself at the notorious Appertoft brothel, desperate for money to support her ailing mother and younger siblings. Her father perished at sea, his assets confiscated. Two gentlemen from the esteemed Allstedt household approach her, offering a substantial sum of 100 gold coins for her to become the mistress of their master, Klaus Allstedt, and to die for him. Intrigued by the offer and the gentlemen's refined demeanor, Olivia accepts, seeing it as a far better fate than the brothel.
The gentlemen, Tobias and Connie, explain the peculiar situation of the Allstedt family. Klaus, a reclusive scholar, is the last male heir of a lineage cursed by his grandfather Adolphe's mistress, Camilla. Camilla, a noblewoman scorned by her husband's infidelity, cursed the Allstedt men who fall in love, decreeing that their beloved women would die on a full moon night in December. This curse has claimed Klaus's father and grandmother, and it is believed to have claimed his mother as well, though she was not Adolphe's true love. Klaus, to avoid this fate, has never seen a woman and lives in isolation, dedicating himself to ancient texts. The Allstedt family, desperate to break the curse and continue their lineage, has hired Olivia to be Klaus's wife and the one to break the curse by dying for him.
Olivia is brought to the grand Allstedt mansion, a place filled with opulence and a palpable sense of history. She is overwhelmed by the luxurious surroundings and the sheer volume of high-quality clothing and accessories provided for her. Her initial interactions with Klaus are awkward; he is visibly shocked by her beauty and struggles to maintain his composure, often resorting to hiding or denial. Despite his initial resistance, Klaus is clearly captivated by Olivia, though he attributes it to surprise and a strange phenomenon. Olivia, in turn, finds him intriguing, a stark contrast to the men she has encountered. She learns that the curse prevents any flowers from blooming in the mansion's garden, a testament to Camilla's lingering influence.
As Olivia settles into her new life, she begins to assist Klaus with his scholarly work, demonstrating a surprising aptitude for languages and deciphering texts, a skill honed from her father's business dealings. She also takes on household chores and tends to the neglected garden, determined to bring life back to the estate. Her interactions with Klaus become more frequent and less strained. He is fascinated by her intelligence and resilience, and she finds herself drawn to his earnestness and hidden vulnerability.
A significant turning point occurs when Olivia discovers the true nature of Camilla's curse. Through meticulous research and the discovery of a hidden music box, it is revealed that Camilla's curse was not one of malice but of a desperate plea for her husband, Adolphe, to acknowledge her pain and love. The "silver needle" was not a weapon but a symbol of her suffering, hidden within the music box, its melody playing a broken tune. Olivia, understanding Camilla's longing for recognition and love, confronts the lingering curse.
The climax arrives on the night of the full moon in December. Olivia, having fulfilled her role and understanding the true nature of the curse, is prepared to meet her fate. However, Klaus, having fallen deeply in love with Olivia, declares his love for her, breaking the curse. He realizes that Camilla's curse was a desperate cry for attention, and his own isolation had mirrored her pain. The curse is broken not by Olivia's death, but by Klaus's genuine love and acceptance of Olivia, and by Olivia's empathy for Camilla. The story concludes with Olivia and Klaus embracing their love, the curse lifted, and the possibility of a future together, free from the shadows of the past.