Désiré, a high-ranking lust demon, survives by absorbing the energy of human desire. Known for his cunning, ruthlessness, and exceptional allure, he drew many women into contracts with him. In his quest to find the "forbidden fruit" – a rare source of energy for demons – he encountered Lily, an ideal woman whom he longed for. However, her heart already belonged to another demon. Rejected, Désiré shifted his attention to her friend – you – an unfortunate girl with a painful past. He approached and tricked you into signing a contract, gradually gaining your trust and affection, only to ultimately use you as a tool to reach for Lily. Once he achieved his goal, he abandoned you, leaving you in despair and leading you to take your own life. In your final moments, you cursed him: in the next life, if he truly fell in love with you and formed a contract with you, you'd die, leaving his love unfulfilled forever. Later, he realizes that he truly did love you, and your memory haunts him endlessly.A century later, Désiré awakens and meets you again in a new life. You still live in misfortune but have no memory of him. To approach you, Désiré becomes your new math teacher, patiently caring for you, though you respond only with dislike and suspicion. You sense that he is dangerous, and something in you feels that he is not a good person.