Shendu is being tortured by his brothers and sisters following the sealing of the final portal to the mortal world. However, he reveals that he has one final plan to secure their collective victory, involving the Book of Ages. The other demons are reluctant, noting that manipulating the Book of Ages risks altering reality itself, but the allure of finally escaping imprisonment and regaining their empires convinces them to let Shendu try his plan.

In the mortal world, the Chans are visiting Jade’s parents, taking great pains to hide their adventures for fear that it might sour them to letting their daughter stay with her relatives. While sitting down for tea, Shendu’s spirit emerges from the Netherworld and finally possesses Jackie. Despite their best efforts, Tohru, Jade, and Uncle are unable to stop Jackie from escaping the house in dramatic fashion; Jade’s parents confine her to her room, unsure if they should allow her to continue staying with her “reckless” uncle.

Using Jackie’s body, Shendu travels to a mysterious temple in Australia that houses the Book of Ages, a powerful magical artifact that automatically records the history of the world. By writing in the book, Shendu alters reality; Jade attempts to interfere, but only succeeds in tearing off a piece of a page before being enveloped in light. When the light fades, Jade finds herself in a vastly altered world; civilization is in a feudal state, magic and martial arts are outlawed, and humanity is enslaved by Shendu and his siblings, each ruling a different area of the world as the Eight Emperors.

After sneaking away from her new house, Jade discovers that her relatives are working in Shendu’s castle; Uncle is the royal bookkeeper, and Jackie is a meek personal attendant to the demon dragon himself. She soon realizes that the torn-out part of the Book of Ages carried her role in the future; since Shendu couldn’t overwrite it, her memories of the old reality remain. Realizing that there’s only one way to save the world, Jade recruits Jackie and Uncle in a desperate plot to reach Australia (now called the Forbidden Country) to undo Shendu’s changes to the Book of Ages. Using the spell Uncle used in the old timeline, they sneak into Shendu’s bedroom to steal the Talismans from his body, only for the demon himself to awaken and attack…