Bok-soon (Kim Go-eun), who runs a street stall, lives with her only sister. Although she has some shortcomings, Bok-soon is a famous "crazy woman". Once you offend her, you will get into big trouble. One day, a cold-blooded killer named Tae-soo (Lee Min-ki) appeared in front of Bok-soon. In order to hide his secret, Tae-soo also harmed her sister. In order to avenge her sister, Bok-soon took up the knife without hesitation, and Tae-soo planned to kill Bok-soon to save trouble. The killer's monologue: Someone once told me that people who are not afraid of anything are the most terrifying. I killed many people without hesitation. Whoever agreed to my request for help, I would kill that person too. But today, I met a strange woman, a crazy woman who is alive like a zombie. It seems quite interesting. Bok-soon's monologue: Although I can't compare with other people's life and ability, I am a person who keeps promises. I once swore to my grandmother that I would never let anyone hurt my sister's hair. Today, I met a cold-blooded killer without blood and flesh. I will definitely chase him to the end. Did he really kill my sister?