Lu Chen, the Sword Sovereign of the Immortal Realm, returns to the mortal world against all odds to avenge the massacre of his family. Accompanied by his childhood friend and confidante Su Muwan and his younger sister Lu Qingyuan, who is skilled in medicine, he embarks on a journey of revenge. Along the way, they defeat powerful factions one after another and gradually uncover the many conspiracies of the Nine Nether Pavilion. After overcoming countless dangers and following every clue, they finally discover that the current emperor, Xiao Hongyuan, is the mastermind behind the tragedy. With his formidable cultivation, Lu Chen vanquishes all his enemies and secures justice for the more than one hundred members of the Lu family who lost their lives.