Lee Sang-yoon (actor Kim Woo-bin) wanted to become a prosecutor like his dad who was admired for his unshakable integrity. But after failing to pass the bar exam several times, he finally passes the bar one day, which is also the day when he kills a woman by accident. He decides to confess his crime but he lets himself be convinced by his mother to keep it a secret and not disappoint his father. The woman he killed was the girlfriend of Joon-ha (actor Song Chang-ui). Joon-ha’s brother, who had a criminal record, decides to confess to the crime so that Joon-ha won’t have to go to jail and their mother dies from grief after the judge sentences her son to life in prison. Joon-ha becomes driven to pass the bar exam and it takes him three years to finally pass the bar, giving him a chance to prove his brother’s innocence. After deferring his law trainee program and leaving the country for two years, Sang-yoon returns to Korea and enters the law trainee program where he befriends Joon-ha. He then learns that Joon-ha’s brother is serving a life sentence for a crime that was committed by none other than himself. He also finds out that Joon-ha’s mother died from grief that her son was sentenced to prison. Though he should have asked for forgiveness from Joon-ha, he turns into a wicked person. Later on, he becomes a cold-blooded person who misuses the law to serve his own interests. When Shin Young-joo (actress Kim Yu-mi) finds evidence that tacks the murder on Sang-yoon, he dangles the prospects of marrying her to manipulate her. Joon-ha reopens the murder case of his late girlfriend when he gets furious from the revelation that Woo-bin could be the killer. Unaware that his career is in jeopardy, Woo-bin is promoted as a partner to his law firm. One day, Woo-bin is stunned when his father confronts him and asks, “Did you kill that woman?”