在这部怪物惊悚片中,经营地摊的福顺（金高恩饰）和唯一的妹妹相依为命，虽然有点不足但福顺是出了名的“疯女子”，只要一得罪她便等于惹了大祸。某一天在福顺面前出现了一个冷血杀人魔泰秀（李民基饰），为了隐瞒自己的秘密泰秀还加害于她的妹妹，为了替妹妹报仇，毫不犹豫拿起刀的福顺，而泰秀省得麻烦，也打算干脆把福顺也杀死。
杀人魔独白：
曾经有人和我说过，不畏惧任何东西的人才是最可怕的，我杀了好多人，毫不犹豫的，谁答应我帮忙的请求，我会连那个人也杀掉。但在今天，我却碰到了个奇怪的女人，一个行尸走肉活着的疯女人，好像挺有意思的。
福顺的独白：
虽然我比不起其他人的生活和能力，但我是个很守约定的人，我曾经对奶奶发誓，我绝不会让任何人伤害妹妹一条头发，今天，我却遇上了一个没血没肉的冷血杀手，我一定会追杀到底。他，真的杀了我妹妹？
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?
《怪物》内涵解说。这个是个怪物横行的世界。怪物之我只想要个妹妹。每个人都是怪物。结局让人倒吸一口气......。女主才是真正的怪物。女主也是怪物。怪物，一个博主的评论，让我个人觉得他诠释了这部电影的黑暗一角。怪物。尼玛怎么看啊。
