A woman dies after rescuing a black cat and is reincarnated into the world of a novel she read in her previous life. She awakens as Alice, the villainess destined to be coldly treated by her husband and ultimately driven to suicide. Refusing to accept that fate, she decides to fully embrace her role as a cruel, unlovable villainess, reasoning that if she is not loved, she can at least survive by being hated. She resolves to make use of everyone around her purely for self-preservation.

Alice is offered an engagement to Elias, the Duke of Rodin, a man with a complicated past and hidden motives. When they meet, he proposes a contract marriage: one year of playing the part of his ornamental wife. She accepts, expecting a cold transactional arrangement. However, her attempts to act as a villainess backfire. Elias begins to dote on her, her family acts strangely when she cuts ties with them, the black cat she rescued turns out to be a god, and fairies appear when she tends to flowers. What was supposed to be a simple performance becomes increasingly complicated as she finds herself genuinely cared for despite all her efforts to push others away.

The story is set in a fantasy aristocratic society centered on the royal court and noble houses, with magical and supernatural elements woven in. The main characters are Alice, a pragmatic and stubborn reincarnator who prioritizes survival over love, and Elias, a cool and handsome duke with his own secrets who unexpectedly falls for her. The narrative arc follows their one-year contract marriage, moving from a pragmatic arrangement to a deepening, affectionate bond, and concluding with the completion of their agreement and the realization that her feelings have become real.