Seo Ji Ahn, a former rich girl, was forced to be her family's breadwinner after her father's bankruptcy. She is now a contractual employee and living her life with restrained emotion. The drama chronicles her struggles to find new meaning and happiness in life.

Cha Woo-Hyuk, a prosecutor who will do anything to take revenge, meets married actress Han Jung-Won and falls in love with her. Han Jung-Won's husband is the son of a chaebol family. Cha Woo-Hyuk then prosecutes Han Jung-Won, the suspect in the murder of Han Jung-Won's husband.

On the day the 15-year statute of limitations expired on a high profile serial murder case that claimed the lives of 10 women, a family member of the victim throws himself off the building in front of Choi Hyeong-goo, the detective in charge of the case. Two years later, a man called Lee Doo-seok publishes a book titled "I am the Murderer" claiming responsibility for the murders that took place 17 years ago. His book becomes a bestseller because of the author’s charming looks and his vivid depiction of the crime. The detective and the self-proclaimed murderer meet face to face on a television debate show. Believing that Lee is nothing but a con artist, Detective Choi renews his search for the ultimate truth. Then another man appears suddenly, claiming he is the real killer.