Psychopath Diary, the new tvN drama to be directed by PD Lee Jong-jae (100 Days My Prince), has secured its leads in Yoon Shi-yoon, Jung In-sun, and Park Sung-hoon.
The upcoming series tells the story of a man who witnesses a murder and loses his memory when he gets into an accident while running away from the scene. When he wakes up with no recollection of his identity and what happened, he starts to believe that he is a murderer because of a diary that is now in his hands. The diary, which contains the gruesome details of how someone was murdered, belongs to the real killer.
That man is Yook Dong-shik, who will be played by Yoon Shi-yoon (Nokdu Flower), a soft-hearted fund manager at a securities firm whose kindness is often exploited by others. His weak personality changes when he starts to perceive himself as a criminal because of the diary.
Meanwhile, Jung In-sun (Terius Behind Me) signed up for the role of Shim Bo-kyung, a rookie police officer who wants to follow the footsteps of her detective father but ends up ignoring her dreams and is stuck with doing her patrol duties. After hitting Dong-shik with her car—the accident which causes him to lose his memory—she plans to catch the real murderer.
Park Sung-hoon (Justice) will play the real murderer named Seo In-woo, a meticulous director at the company where Dong-shik is employed. He is a psychopath who exerts his influence over other people by killing them. He manages to keep his secret without any problem until his diary falls into the hands of Dong-shik.