The film tells the story of Gwanghaegun who was crowned as the crown prince during the Japanese invasion of Korea in 1592. After King Seonjo fled, he fought alone to protect the country. The film unfolds the story from the perspective of the warriors who protected Gwanghaegun. "Dailing Army" refers to the story of the poor and powerless people in the Joseon Dynasty who joined the army instead of the rich and powerful nobles.