The Book of Bill

The Book of Bill directly builds on and often references the 2012-2016 show Gravity Falls. Bill Cipher was the primary antagonist of Season 2 of Gravity Falls, and many of the details within the book—his henchmaniacs, the Zodiac prophesied by the Shaman, the Nightmare Realm, and more—all directly appear in the show, although often with less detail and backstory. Gravity Falls centered on 12-year-old twins Dipper and Mabel Pines, sent to live with their great uncle, “Grunkle” Stan, for the summer. This event is revealed in The Book of Bill to be because their parents are divorcing. Stan runs the Mystery Shack, a laboratory-turned-house and tourist trap.

Over the course of two seasons, Dipper and Mabel explore Gravity Falls’s weird, mystical, and often dangerous terrain, discovering magical creatures and strange secrets about the town’s history, land, and people. Dipper’s storyline focuses on three journals by the Author, revealed in season two to be Stan Pines’s twin brother Stanford, who Stan has been pretending to be for 30 years after Stanford was sucked into a portal to the Nightmare Realm. After Stanford returns, Bill manipulates Mabel into opening a rift between realms, allowing him to initiate Weirdmageddon, although Gravity Falls’s protections prevent him from enacting his apocalypse outside of the town’s borders without a code from Stanford’s brain.