The whole people collectively entered a flood-immersed survival world, and everyone was trapped on small rafts, with resources in short supply. The protagonist Lin Bei accidentally contracts an ancient black turtle and builds a mobile city-state called Xuanwu City on the back of the turtle. He reclaimed farmland, built workshops, took in displaced survivors, and built a low-price trading house without exaggerating supplies. Facing the predatory forces floating on the sea, Lin Bei relied on city defense to passively defend against the enemy, and led the people to work together and divide labor for symbiosis. The series abandons the jungle mentality of the weak and the strong, and tells a positive story that only through mutual help, co-construction, and abiding by order can mankind survive for a long time.
