The world has been reduced to rubble by a massive earthquake. While no one knows for sure how far the ruins stretch, or what the cause of the earthquake may be, in the heart of Seoul there is only one apartment building left standing. It is called Hwang Gung Apartments. As time passes, outsiders start coming in to Hwang Gung Apartments trying to escape the extreme cold. Before long, the apartment residents are unable to cope with the increasing numbers. Feeling a threat to their very survival, the residents enact a special measure.

Kim Dok-ja, an ordinary man in his 20s, is the only reader of an obscure web novel titled "Three Ways to Survive the Apocalypse". After having read the last chapter, the novel suddenly becomes reality, and its omnipotent hero Yu Jung-hyeok appears before Kim. As the only person who knows how to survive in this world, Kim and his companions strive to save the world by writing his own, new ending.

After spending a decade in prison, a hitman learns that he has a daughter and just wants a chance at a normal life. But his former mob boss wants him back at any cost, sending merciless assassins after him.

When a raging flood traps a researcher and her young son, a call to a crucial mission puts their escape — and the future of humanity — on the line.