Yoon Si Yoon, Jung In Sun, and Park Sung Hoon will be working together for a new tvN crime/mystery drama, 'Psychopath Diary'. 

The drama tells the story of a man who happened to be a witness at a murder crime scene. While running away from the crime scene, he loses all of his memories. He wakes up to find that he's in possession of a mysterious diary, documenting every detail of the murder. This leads him to believe that he himself is the psychopathic killer. 

Yoon Si Yoon will take on the role of the male lead Yook Dong Shik - a man trying to cope with the fact that he was a "psychopathic killer" before losing all of his memories. Jung In Sun takes on the role of a neighborhood police officer named Shim Bo Kyung, who becomes entangled in Yook Dong Shik's life due to an accident. Finally, Park Sung Hoon plays the role of the real psychopathic killer, Seo In Woo. 

'Psychopath Diary' is expected to air some time in the latter half of 2019. Do you find the storyline interesting so far?