The story of Lin Wanxing, who possesses the power of the star core, and Mo Yuan, who possesses the power of darkness, use the Symbiosis Pendant to maintain the bond between yin and yang and protect the world. Five years after the Frozen War in the Far North, three boundary gates in the Hidden Mist Mountain, the Sand Sea in the West, and Penglai in the East China Sea suddenly changed. The rule devourers from outside the plane carried the erosion stones to erode the power of Yin and Yang, trying to break through the gates and swallow the rules of the world. Under the crisis, Lin Wanxing and Mo Yuan gathered Yan Li, a descendant of the border warrior clan, Lin Yue, the ancient book god, and Ling Luo, a former member of the assassination organization. The five of them shared perception and complementary combat power with the help of bond tokens. They attacked separately and defeated the Devourer's leader in the Sand Sea with the power of flames and darkness. In Penglai, they worked together to awaken the Poseidon Guardian Array to thwart the evolved Devourer, temporarily resolving the three world gate crises. But the main force of the Devourers behind the Realm Gate is still gathering. An ultimate plane battle concerning the survival of the world is waiting for this guardian team with the power of Yin and Yang as its core.
