This novel mainly tells the story of the "King of Assassins"—a legendary assassin—who accidentally falls off a cliff, traverses to the Jiuchen Continent. However, he becomes the laughingstock of his family and endures constant ridicule because he cannot awaken a Dao Soul. Just before he is about to be expelled from the family, Yang Yu miraculously activates the Dao Mansion Divine Palace and finally awakens his Dao Soul. Unexpectedly, the Dao Soul he awakens turns out to be the lowest-ranked and most useless "Medical Book Dao Soul." Yang Yu once again becomes a laughingstock and even falls prey to schemes from various parties. When he is overwhelmed by despair, he discovers a great secret hidden within himself: the appearance of the "Book of Ten Thousand Daos" allows him to embark on a cultivation path completely different from that of ordinary people. To rescue his dearest younger sister, to revive his beloved, to avenge his master, to uncover the truth behind the ancient upheavals, and to restore the former glory of the Divine Race... Yang Yu sets out on his journey. He devours countless Dao Souls, integrates himself with ten thousand Daos, slays saints and eliminates demons, and finally breaks free from the constraints of Dao. In the end, he makes ten thousand Daos submit to him alone!