"I want to be you" is a sharp psychological thriller fueled by jealousy. The story connects Min-hee, a class president whose identity is being stolen by a social outcast, and Ah-reum, who returns home after 16 years to care for her reclusive brother. Their lives violently collide during a brutal "Mother-Daughter Murder Case," where a lone witness confesses a chilling, bizarre scene to a detective, reconstructing the tragic events of that fateful day.

正顺是一位在食品厂工作的中年单身妇女，她和工厂同事永洙在秘密交往。幽会途中，永洙偶尔会用手机拍摄正顺。有一天，正顺感觉到她的同事们在都背后议论她。当她开始寻找问题所在，才发现是永洙把她的视频传播给了他们的同事，她的世界一瞬间土崩瓦解。