"Weirdmageddon 3: Take Back The Falls" is the 20th episode of the second season of Gravity Falls and the fortieth episode overall. It is set to premiere February 15, 2016 and will also be the third and final episode in the Weirdmageddon story arc as well as the hour–long series finale.
Ford discovers Bill’s true motives and then a final confrontation with Bill leads to the Pines family’s ultimate fate and greatest sacrifice.
↑ 2.02.1Hirsch, Alex. Goodbye Gravity Falls (Tumblr post). Archived from the original on November 21, 2015. Retrieved on November 21, 2015. “There are two more episodes left: 'Weirdmageddon II: Escape from Reality' and 'Weirdmageddon III' which will be our hour long series finale.”
↑Mitovich, Matt Webb (2015-11-20). Gravity Falls to end in 2016. TVLine Media, LLC.. Retrieved on November 20, 2015. “The animated series has two more episodes left: 'Weirdmageddon II: Escape from Reality,' airing Nov. 23, and the hour-long series finale, 'Weirdmageddon III,' to follow sometime in 2016.”