Kang Hanuel, an ordinary young man in Seoul, wakes from an afternoon nap to find the entire city plunged into total darkness — no electricity, no stars in the sky, and everyone dead. As colossal insect-like creatures roam the streets transforming remaining survivors into something inhuman, he meets Shin Heyoo, the only other person still alive, and together they must cross the dead city toward a faint hope on the southern horizon — before the darkness changes them too.