33-year old Je-In is a mystery novelist who is notorious for habitual false reporting to the police in town. Her only friend is police officer Rock-hwan, who has had a crush on her since childhood. One day, Jane 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 Rock-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.