The protagonist travels to a declining cultivation family and discovers that he is bound to the family's ancestral magic weapon - the "Xuanyin Soul Refining Coffin" and becomes its weapon spirit (or symbiotic host). Facing the desperate situation of depleted resources, surrounded by powerful enemies, and strange natural disasters, he must use modern knowledge and sound strategies to lead his people to survive in the darkness, build his family as the last refuge, and finally reveal the truth that the world is shrouded in the "strange night."
