Hitomi, a Japanese resident, comes to Hong Kong after the death of her fiancé Tatsuya in a fatal accident to settle several important matters surrounding his demise. Although the incident was years ago, it has apparently left an indelible mark in her life as she could not forget him. Kar Bo, an undercover cop, was involved in a drug bust-up which would later incriminate him. Hitomi stumbles into him and was amazed that he looked remarkably similar to her dead lover. Although Hitomi was conscious that Kar Bo can never be the real Tatsuya, she endures his hardships with him unfailingly which results to having strong feelings for each other.
33-year old Han Je In is a mystery novelist who is notorious for habitual false reporting to the police in town. Her only friend is police officer Rok Hwan, who has had a crush on her since childhood. One day, Je In hears a scream of help from an apartment upstairs and reports that a serial killer lives above her but no one believes her. Convinced that Jason, the handsome man living upstairs, is a serial killer, she asks Rok Hwan to help follow him around with her. But as she learns more about Jason in her pursuit to uncover the truth, she begins to fall for him. Seeing her in this state, Rok Hwan feels a tinge of jealousy.
