13 years after the King Injo Revolt, the Chosun Dynasty is attacked by the Chung Dynasty of China. A young man named Na-mi leaves his demolished village to find his young sister, Ja-in, and her finance Su-koon, who were to wed on the very day of the attack. While on his mission to rescue her, he is being traced by Jushinta, a fierce Chung Warrior, and his band of malicious men who are out to stop him. Na-mi has but a day to rescue his sister before she is taken away to be a slave. When Na-mi finally finds his sister, Jushinta comes between them and a fierce battle between two of the finest warriors unfolds.

Set in 1398. Kim Min-Jae (Shin Ha-Kyun) is the supreme commander of the Joseon Dynasty. He falls in love for the first time and for that woman he takes risks. Yi Bang-Won (Jang Hyuk) is the King’s son. He helped his father setup the Joseon Dynasty era, but he was not picked as the Crown Prince. He still holds ambitions of becoming the King one day.
Jin (Kang Ha-Neul) is Kim Min-Jae’s son and the King’s son-in-law. Due to his position as the King’s son-in-law, he is unable to take part in politics and only seeks out pleasure.

The film is based on a true yet unsolved murder case from the early 1990s that is known among Koreans as the “disappearance of the frog children.” In 1991, five elementary school students told their parents that they were going to hang out on a nearby mountain to catch frogs, and then they go missing.