Hee Woo is a prosecutor known for his rather crazy methods. He starts investigating Cho Tae Sub, a man who wields the utmost power in the running of the country. During the investigation, Hee Woo realizes that he has died. However, the woman he meets after his death gives him a second chance at life and revenge.

Hee Woo goes back to living as a 21-year-old. He realizes that he can actually change the course of his life and does his best to live life to its fullest. Meanwhile, he keeps remembering events from his past life that he thought was unfortunate and changes their outcomes. Later on, Hee Woo goes back to being a law student.

Hee Woo settles into his life as a college student once more and gets started on his revenge against Cho Tae Sub in earnest. He seeks out teachers to help him get ready for the long-term fight that lies ahead. In the process of doing so, Hee Woo meets an elderly gentleman, known as the master of auctions.

Hee Woo continues to keep a close eye on Cho Tae Sub’s actions. One day, Min Soo introduces Hee Woo to a friend of his who has a brilliant idea. Sung Hwan is a former med school student who has now developed an idea for a smartphone application. Knowing that this will benefit Cho Tae Sub if he doesn’t step in, Hee Woo decides to help Sung Hwan.

Hee Woo helps change the life of Sang Man and his dad before he goes off to serve in the military once again. Seven years go by, and Hee Woo returns as a prosecutor. However, he volunteers for a position at a small country branch office instead of Seoul. As he starts to look into local crimes, the name of a gang continues to grab his attention.

Hee Woo’s quest to get to the bottom of corruption and crime in Gimsan continues. He finally reveals to Seok Kyu that he intends to take everyone at the Gimsan Branch Office to Seoul with the success of this case. Meanwhile, Hee Woo reconnects with his friends from college as they all play a role in Hee Woo’s grand scheme.

After successfully shutting down the case in Gimsan, Hee Woo returns to the Seoul Central District Prosecutors' Office. As Hee Woo gets closer to Cho Tae Sub and his inner circle, Il Hyun begins to show his true colors. Meanwhile, a medical student becomes the leading suspect in a murder case, but Hee Woo suspects something is amiss.

The med student Lee Ju Seok desperately pleads his innocence, but Jang Il Hyun has no intention of listening. However, as Hee Woo steps in and proves Ju Seok’s claim, everything goes down for Il Hyun. His loss destroys everything that the higher-ups are trying to cover up for CEO Jeon Il Bo. For the prosecution, Il Hyun is now nothing but a tail to cut loose.

Hee Woo’s plan to take down Il Hyun pans out as a success when he is arrested on bribery charges. However, Hee Woo continues to work with his friends, Kyu Ri and Min Soo, to go after Kang Jin as well. Meanwhile, Hee A keeps refusing to accept Gun Young’s suggestion that she must be the successor of Chunha Group. Then, Hee Woo becomes acquainted with Assemblyman Hwang Jin Yong.

Assemblyman Hwang Jin Yong reveals the names on the list to the public. With almost a hundred politicians being on that list, the corrupted fall into panic. However, Cho Tae Sub sees this as an opportunity. He increases his power by bringing in all the dirty politicians under his control in exchange for redemption. As the list did not hit as hard as Hee Woo thought it would, he does not stop here.

Chairman Kim Gun Young tries his best to hold off Cho Tae Sub’s greedy advances for Chunha Group and names Hee A his successor. However, Cho Tae Sub decides to take Chairman Kim out of the equation for good. Meanwhile, Hee Woo reacts to Cho Tae Sub’s advances by offering Hee A his help, but Hee A is wary of his intentions.

As Hee Woo’s plans to take down Chief Prosecutor Kim Seok Hoon continue, he finds himself in a precarious position between the chief prosecutor and Assemblyman Cho Tae Sub. In order to find the dirt on Kim Seok Hoon, Hee Woo and his friends dig into Bando Bank’s corruption and JQ Constructions.

Hee Woo and his colleagues finally take down Kim Seok Hoon using his wife and son’s corruption and Kim Seok Hoon’s own unethical life. Cho Tae Sub now seeks a new nominee for the next prosecutor general. Meanwhile, Hee Woo, Sang Man, and Hee A hear about JQ Constructions becoming available for acquisition soon and begin their plan to make a bid.

Seok Kyu, the new Chief Prosecutor, tells Hee Woo to take his hands off of the Kim Seok Hoon case and transfers him to a different team. Hee Woo knows that Cho Tae Sub is the one behind this order, but he decides to keep going with his plan to take down the people closest to Cho Tae Sub himself. When Hee Woo goes after Park Dae Ho, Cho Tae Sub starts to strike back at Hee Woo.

After taking down Cho Tae Sub’s allies and underlings, Hee Woo resigns from the prosecution. In a surprise move, he announces his candidacy for the National Assembly in the same constituency as Cho Tae Sub himself. In a heated election, ripe with smear campaigns and false accusations, Hee Woo gears up for the final showdown.