A security analyst Yook Dong-sik witnesses a murder. He grabs a diary of the murderer and flees. However, he accidentally gets hit by a car, experiences a memory loss, and thinks himself as the culprit.
EPISODE 1
Episode 1
Yook Dong-sik gets fired from his company for a mistake of his superior. Dong-sik witnesses a murder when he is about to take his own life.
EPISODE 2
Episode 2
Dong-sik mistakenly believes that he is a psychopath. The real murderer, Seo In-woo, starts to look for his lost diary.
EPISODE 3
Episode 3
Dong-sik devises a plan to murder Seo Ji-hoon. The work colleagues do not know what Dong-sik thinks. Knowing what has happened, In-woo approaches Dong-sik.
EPISODE 4
Episode 4
Dong-sik successfully kidnaps Ji-hoon. Dong-sik gets promoted thanks to his work performance being appreciated and recognized in the company.
EPISODE 5
Episode 5
In-woo and Bo-kyung follow Dong-sik with different motives of their own. Bo-kyung discovers a pattern of serial killing thanks to Dong-sik.
EPISODE 6
Episode 6
In-woo realizes that Dong-sik is working with Bo-kyung to find out the true culprit of his murder cases. Dong-sik feels confused after knowing what happened to Hong Jin-gu.
Yoon Shi-yoon
Jung In-sun
Park Sung-hoon
Lee Han-wi
Jung Su-bin
Choi Sung-won
Lee Jong-jae
Choe Sung-jun
Kim Hwan-chae
Ryu Yong-jae
