tvN’s 2019 drama series Psychopath Diary (싸이코패스 다이어리) is a hilarious, darkly comic thriller that utilizes the strengths of its cast to support a wild, exciting and fast-paced ride.
Yook Dong Sik (Yoon Shi Yoon in a role made for him) is a timid young salaryman working at a brokerage firm where he gets pushed around and looked down upon. The pressures of his daily life and the hurtful perceptions of people around him have him considering suicide. But when he talks himself off a ledge, literally, he unintentionally witnesses the latest murder by a psychopathic serial killer.
That serial killer happens to be the director at his brokerage firm, Seo In Woo (brilliantly brought to life by Park Sung Hoon), who keeps a detailed diary of all his murders. Dong Sik picks up the diary as he runs away.
But after officer Shim Bo Kyung (Jung In Sun) accidentally hits him with her patrol car, Dong Sik suffers retrograde amnesia. Not remembering anything before the accident (including his timid personality), he believes the diary belongs to him and that he is the psychopath predator killer. Now Dong Sik embraces that murderous personality even if he isn’t too sure how to live as one other than what’s written in the diary.
That initial set-up results in Psychopath Diary being a hilarious and tense-filled adventure with Dong Sik bumbling his way through being a supposed serial killer while In Woo continues to relish in his extracurricular activities. Once In Woo realizes what has happened with Dong Sik and his diary, he instigates a dangerous cat and mouse game (with a twist) that only enhances his fun (to him) hobby.
At its core, Psychopath Diary is a fascinating look at today’s culture in which people can be selfish and how they can take advantage of other people for various reasons. Whether it be for superficial, selfish benefit or just for self-preservation, the series bluntly exposes another sad reality of today’s work and societal culture.
That harsh world can drive people to do bad things. While it certainly doesn’t justify those questionable decisions, it nonetheless shines a light on the mental and physical struggles that people may go through. It also shows how difficult it can be for someone to change their personality for the better or just find that extra bit of courage and confidence in themselves.
The series is able to also remind us of the forgotten and uncared for people in society and how they too can be manipulated and used by others with nefarious intentions.
Psychopath Diary is able to do all this with a careful balance that requires some threading through a small needle. But it is key to understand what this series is and what this isn’t. While the idea of a serial killer on the loose and the relatively violent depictions of the murders can seem grim, the focus of the series is much more about the characters and where they’re coming from.
Being able to meet, learn and understand these characters becomes much easier to when the series is able to seamlessly weave in lighthearted and downright hilarious moments to counter the relatively darker and more sinister elements of the story. The lighter moments serve as a welcome contrast, but also helps to drive character growth and plot development as well.
As enjoyable as the story is, the cast is definitely the series’ strongest aspect.
The role of Yook Dong Sik is absolutely perfect for Yoon Shi Yoon. The series fully utilizes Yoon Shi Yoon’s signature versatility. The duality of Yoon Shi Yoon to make you laugh out loud one minute and cry like an emotional wreck the next is a definite talent that he perfects more and more with each project. His talent and charm immediately pulls you into the story and onto his side. And it’s hard to see any other actor in this role besides him.
Jung In Sun herself has shown off her versatility over the many projects she’s had over the years as well. Whether it is comedy or drama, she is able to always project a confident character that has you believing and trusting in her from the start. She gets several opportunities for some strong, emotional moments here as Bo Kyung that are definite highlights.
Kim Myung Soo plays Bo Kyung’s father Shim Seok Gu in a unique dual role that sees him as an illusion from her subconscious as the star detective he once was and in his current state suffering from dementia after a fall during an investigation. As the hallucination, he is able to give wise fatherly advice to Bo Kyung as well as play the old-school, no-nonsense detective. As the current, real-life version, Kim Myung Soo effectively serves as an emotional connection for Bo Kyung that helps build her character and results in one of the most satisfying moments in the end.
Heo Sung Tae matched up against Yoon Shi Yoon in Your Honor as a corrupt lawyer and sexual predator. Here, he is an absolute hilarious scene stealer as reformed gangster Jang Chil Sung who pledges loyalty to his reluctant boss Dong Sik.
And finally, the chilling performance of Park Sung Hoon as Seo In Woo. Playing a psychopath serial killer offers up some great opportunities for an actor to play around with. Park Sung Hoon grabs every single one of those opportunities and then some. Seeing how much he relishes in the role gives the series the tension and dark aura it needs to be a complete story. And as the series again is well-balanced between the lighter and darker aspects, Park Sung Hoon never misses a beat. And that allows for In Woo to be a legitimate threat every single minute of the series.
While the series may not have touched upon the origins of his emotional pain as deep as it could have, this was a standout and breakthrough performance by Park Sung Hoon who undoubtedly will be getting many more opportunities (hopefully as a lead) in the future.
Overall, Psychopath Diary is a hell of a ride. Amazing performances pull you along for an enjoyable and eye-opening adventure that is equal parts hilarious fun, edge of your seat thrills and heartfelt emotional moments.