Hiding Out In An Apocalypse summary:

Three years ago, a doomsday prepper named Park Kyu, who predicted the world’s end and prepared for it in every way possible. As he expected, one day, a nuclear attack on Seoul led to a global nuclear war, resulting in an unprecedented apocalypse.Despite everyone’s ridicule, the protagonist Park Kyu spent his entire fortune over the past three years to quietly dig out his own bunker. Was it merely a coincidence that he foresaw all these events?