The Great Era of Heavenly Tribulation

When humans are no longer the overlords of the world, terrible natural disasters have caused humans to fall from the top of the food chain, and evolved bugs continue to suppress humans' living space. College student Li Si travels to this strange world and is told that he, who shoulders the destiny of humanity, should lead the entire human race against the endless tide of bugs? How should he make a choice after learning the truth about the struggle for survival?