15 days until the apocalypse happens. That's what Hoyeong Lee, a 29-year-old office worker, learns when he takes the mysterious medicine he got for saving a goblin from a bear trap. As it turns out, it allows him to level up more easily and provides him with a strategy guide! Everyone in the world is forced into groups to conquer the mysterious Apocalypse Tower, and Hoyeong has to find a way to work with his teammates so that everyone makes it to the top alive. Will his ability give him an advantage, or will it end up spelling out his doom?