The world has fallen. Cities lie in ruins, infested with mutant animals. Humans are forced to take shelter in bases. Caravan guards, people with monster-fighting powers, are humanity's only hope. To uncover the truth of his fellow apprentice's death, Lu Renjia begins his career as a caravan guard. He embarks on a journey filled with challenges and conspiracies, one after the next. "l am the strongest iron guard. Nothing and no one stand in my way!" Note: Includes one extra chapter.