In order to escape all kinds of troubles in the demon world, Yi Gu, the "Demon King", ran to the human world, only to find that human society is not that easy to mess with. But after meeting the "cute" Qi Yuan, all the troubles can be resolved by him. While the two traveled around the great rivers and mountains, they also dealt with the little monsters that had escaped to the human world and "become monsters", and various stories unfolded from this.