Kwon Heemang is a jobless recluse living a shut-in lifestyle without a single friend to her name. Her mundane existence takes a supernatural turn after a freak accident grants her the ability to see ghosts, leading to a haunting encounter with Kim Sarang. The lingering spirit strikes a deal: she will leave Heemang alone only after fulfilling her final wish. Sarang died just one month into her first relationship, never having the chance to truly experience intimacy with her boyfriend. Before Heemang can protest, Sarang possesses her body and tracks down her ex, Choi Taemin, a popular, younger student celebrating his return to college after military service. In a bold, possessed frenzy, Heemang catches Taemin off guard with an intense kiss in front of everyone. Shaken and humiliated once the possession lifts, Heemang flees the scene. However, Taemin, who secretly admires assertive older women, finds himself completely smitten by the mysterious "crazy woman" who stole his heart.