Four rookie detectives come from different backgrounds, dreams, and past lives. They bump into each other on the most cherished Gangnam Police Department, which isn't exactly the dream station they hope to find for their career. Dae Koo, Soo Sun, Tae Il, and Kook are led by their team leader Legendary Detective Pan Seok. What Pan Seok doesn't know is that he's dealing with the son of a victim from his one and only mismanaged case. Team 3's out to serve and protect Gangnam's justice system.

This story is about 'desire, mistake, forgiveness, and salvation.' The only power making all of this possible is love. People feel desires throughout their lives. When desires blind us, we make mistakes of making choices we wouldn't have made. That's because we are human beings and because we have to live on and survive. It's not that we were born badly, nor did we have evil hearts. However, sometimes, they demand a harsher price than we have done. Life is about how to take responsibility for mistakes and forgive others.