Yoon Shi-yoon is a South Korean actor. He is best known for his roles in the television dramas Psychopath Diary (2019), Nokdu Flower (2019), Your Honor (2018), Grand Prince (2018), Hit the Top (2017), Secret Healer (2016), Prime Minister & I (2013), My Cute Guys (2013) and Bread, Love and Dreams (2010).
Yook Dong-sik works in a brokerage company. One day, he witnesses a gruesome murder and comes across a diary that contains a detailed list of the murder logs. He flees and gets into a car accident. He lost his memory and thought that he is the psycho serial killer. His personality changes drastically.