Following the ending of Daughter of Bill Cipher, a new adventure awaits in the strange land of Amphibia. After finding themselves stranded, Molly, Darryl, Libby, Scratch, and Anne have to adjust to the new world until they can find a way home.
But along the way, they meet those who are also stranded. The daughter of Bill Cipher, Bella, Billie, Balan, Nights, the Smiling Critters, Frowny Fox, the Digital Circus crew, cute kittens Magenta, Lavender, and Indigo, Dipper, and Mabel, and the newt that have been reported missing for months, Fern.
As they try to get home, they meet many new friends and foes, along with a few surprising secrets. No one knows why, but maybe they were destined to come to the land of Amphibia.
After Weirdmageddon, Dipper and Mabel returned home. Leaving their Gruncles, new friends and childhood behind. Bill Cipher was gone, peace is restored and mysteries solved. But, with the disappearance of Bill Cipher, they felt...weird. They felt incomplete and alone, eventhough they had each other. They felt...empty.
After 4 years, the Mystery twins came back to Gravity Falls and was surprised by the changes of the small and cozy town. And they met the one who filled the hole in their heart, by being an enemy to their whole family...