The world is divided into three realms; the Heavenly Realm, Underworld Realm, and Mortal Realm. Both the Heavenly and Underworld Realms have a role to play; heaven is in charge of maintaining peace in the three worlds while the underworld is in charge of collecting and retrieving the souls of the dead to be transported to the other world or for the next life. Immortal God Yuxuan Zhu is the ruler of the underworld. He is known as a cold-faced but very handsome creature, cruel, brave, strict, responsible and obedient to the law of realms. But his life is messed up after he catches the mermaid Xinyan Gu who wants to steal his magical brush pen. He also learns that the mermaid rescued a father and daughter fishing at sea who must be dead and set to travel to the underworld. She broke what was written in the order of fate for the father and daughter. Lord Yuxuan became angry and punished the naughty mermaid to be his maid for hundreds of years.