When Underworld ghost official Ling Ye was executing a mission, he accidentally broke into a parallel world full of eerie secret realms and joined the Town Ghost Division that guards the mortal world. While investigating bizarre strange cases, he unexpectedly found his long-lost younger sister Ling Xi, who had already become a top lord of the ghost realm. Together with the people of the Town Ghost Division, the siblings pacified various ghost uprisings one after another, thwarted the Blood Ancestor's conspiracy to cross the boundary for invasion, gathered sacred objects to establish the Jiuyou branch office, stabilized the balance between the two realms, and guarded the peace of the world with persistence and family affection.