Dismissed by her stoic arranged fiancé Lee Dowoon for being too innocent, wealthy heiress Han Seri refuses to accept a loveless marriage. To spark passion in her icy relationship, she hires the notorious playboy Oh Hyeonwoo for secret, late-night lessons in seduction. But as Hyeonwoo teaches her the art of intimacy, his teasing touch begins to ignite genuine sparks. What began as a desperate scheme to save her engagement soon spirals into a chaotic, intoxicating love triangle.