"Is Narcissism a Sin?"

Sayaka, a woman with intense narcissistic tendencies, possesses enchanting eyes with a mesmerizing power that captivates men's hearts. As she hunts for her next conquest, she targets a young psychiatrist, Kanzaki, drawing him in by confiding her deepest emotional troubles. She reveals to Kanzaki her heart-wrenching past: recurring arguments between her parents during her childhood, domestic violence from her mother, and restless nights haunted by dreams of her sister's suspicious death. On top of all this, Sayaka claims to be pursued by a sinister stalker.

On the other hand, Kanzaki is burdened by a strained relationship with his authoritarian father, a renowned surgeon, who neglects his family. Kanzaki had chosen psychiatry due to the trauma of not preventing his mentally distressed mother's suicide during his childhood and as an act of defiance against his father. He feels a profound connection to Sayaka, seeing in her a reflection of his own losses.

As their relationship deepens, Sayaka tearfully confesses her doubt: Was her sister's death from falling off a cliff truly accidental? Or did she, in a forgotten moment, push her sister to her doom?

Drawn deeper into Sayaka's enigmatic allure, Kanzaki soon discovers a shocking truth. The stalker Sayaka fears is Noguchi, a straightforward and earnest university professor. It emerges that in their youth, it was Sayaka who had aggressively pursued Noguchi. Ensnared by her bewitching charm, he had lost his family and career for her. Yet unable to let go of their passionate past, Noguchi relentlessly chases Sayaka. One day, upon seeing her with Kanzaki, jealousy consumes Noguchi, leading to a confrontation that unveils Sayaka's true nature to Kanzaki.