Seo Yi-Gang is the best ranger at Jiri Mountain National Park. She knows virtually everything about the area, including where to climb the mountain. Kang Hyun-Jo is a rookie ranger at Jiri Mountain National Park. He graduated from the military academy and was once an army captain. He has a secret that he can't tell anyone about. These two people become partners and they work to save people around Jiri Mountain National Park.

Kyung-min lives alone in a one-room apartment. One day, she found a trace of a stranger breaking into her room and soon a mysterious murder case begins to unravel