King Hyeonjong and Kang Kam-chan led the 8-year-long 2nd and 3rd Goryeo-Khitan Wars to victory and began an era of peace in East Asia and prosperity in Goryeo.
The series focuses at the beginning of the 2nd Goryeo-Khitan War in 1009 and the end of the 3rd Goryeo-Khitan War in 1019; and the recognition of King Hyeonjong by the Liao king in 1022.
The Khitan Empire, also known as the Liao dynasty, was a great power at the time, and Goryeo was an emerging state. As King Mokjong left no heirs from being preoccupied, King Hyeonjong, the last grandson of Taejo of Goryeo, became first in line for succession.
King Hyeonjong, who had been away from politics and living as a monk, ascended to the throne at 19 years of age due to the rebellion by Kang Cho. The young king faced an invasion by a Khitan army of 400,000 men because of it.
Kang Kam-chan, a loyal subject, helped the king during the two wars. The king eventually unified Goryeo with his tolerance and leadership. And Kang Kam-chan annihilated the Khitan army at the Battle of Gwiju in 1018.