When Kim Hee-woo was a high school student, his academic grades ranked at the bottom of his school. Through hard work, Kim Hee-woo entered a university and eventually passed the bar exam. He now works as an enthusiastic prosecutor. While he is investigates possible corruption related to a politician named Cho Tae-seob, he gets killed by an unidentified men. But, Kim Hee-woo wakes up and finds himself alive again.
Set during the Joseon Dynasty period, the series follows three people from different walks of life who came together to help Prince Lee Geum claim the throne and reform the Saheonbu.