709 is a secret organization that studies supernatural phenomena. Its mission is to study events that cannot be explained by science and find out the truth of this world. New agent Jin Mushui and female agent Dong Ling, who has super powers, were ordered to investigate a dragon falling incident in Liaoning in 1934. The two went back to 1934 through a time-space gate to uncover the truth behind the real dragon falling incident in history, but they found themselves in a lot of crises.