In college, Yong-nam was the best rock climber in the school, but his life went downhill after graduation. Unable to find a job, Yong-nam can only rely on his parents for support. His mother's 70th birthday is coming soon, and Yong-nam insists on holding the celebration ceremony in the hotel where his junior Yi-joo works. In the banquet hall, Yong-nam and Yi-joo meet unexpectedly, but what awaits them is an unprecedented disaster. When the toxic gas fills the city of Seoul, they have to use their own abilities and rock climbing skills to escape.