One of the three hallowed mountains of Korea, Mount Jiri has been attracting visitors to its majestic grounds long before the park surrounding it was created. Founded in 1967, Jirisan National Park is the oldest and largest of the country’s national parks, managed by a dedicated team of rangers who have devoted their lives not only to protecting and preserving the park, but the countless visitors who trek through the extensive grounds every year. Among these rangers is the incomparable Seo Yi Kang (Jun Ji Hyun). Considered by many to be the best of the best, Yi Kang’s knowledge of the park and skill as a tracker has saved countless lives. At her side stands Kang Hyun Jo (Joo Ji Hoon), an ex-military lieutenant who decided to become a ranger after experiencing a horrific incident on the Jiri mountain. Though he may be only a rookie, his military experience makes him an exceptional ranger and a reliable partner for Yi Kang. Reporting to Jo Dae Jin (Sung Dong Il), the head of the Haedong Branch Office, Yi Kang, Hyung Jo, and the very practical Jung Goo Young (Oh Jung Se), make up an impressive team of rangers who daily risk their lives to save others. But when mysterious rumors start floating around about the mountain’s unexplored regions, the strength of each member of this intrepid crew is put to the test. Will their skill be enough to unravel the mysteries of Mount Jiri, or will the untamed wilds of the mountain prove to be too much?