Bok-Soon (KIM Go-Eun) runs a street stall while taking care of her younger sister. Bok-Soon may not be the brightest girl but what she lacks in intelligence, she makes up for in uncontrollable rage. She s infamously known as the psycho bitch in her neighborhood. Bok-Soon s relatively peaceful life with her sister is disrupted when they cross paths with a serial killer named Tae-Soo (LEE Min-Ki). Tae-Soo kills Bok-Soon s sister because she may have stumbled upon the truth of his murderous lifestyle. Bok-Soon s rage consumes her completely, leading her to plot her revenge on Tae Soo. Meanwhile, Tae-Soo vows to tie up his only loose end-Bok-Soon. Bok-Soon s descent into revenge and electrifying struggle with Tae-Soo culminates in a riveting conclusion. Who will emerge alive: hot-blooded Bok-Soon or cold-hearted Tae-Soo?