Ning Yechen, the supreme ruler of the Demon Realm, has lived in seclusion for a hundred years. By chance, he encounters Luo Ruying, the Female Emperor of the Immortal Realm, who has been afflicted with a love poison, and the two become bound together by fate. Six years later, Luo Ruying's immortal bones are ripped out and she loses all her cultivation. With their daughter in tow, she comes seeking refuge with Ning Yechen, only to be pursued by assassins from the Immortal Realm. To protect his wife and daughter, Ning Yechen stops hiding his true strength. He sweeps away his enemies in the mortal world and ventures into the Immortal Realm to uncover the truth. With the might of a Demon Venerable, he protects his family from all harm and embarks on a legendary journey across the Three Realms.