In the small town of Gravity Ascends, Pacifica and Gideon expect a quiet summer working at Gideon 's dad's shop. The town's local celebrities, the Gleeful twins, however, have other plans involving a blue triangle demon. Their uncles have assigned them a mission to obtain all three journals in order to summon Will Cipher, a dimension travelling demon. Will the duo take over all the alternate universes, or will Pacifica and Gideon beat them to it?
Dipper Pines along with his twin sister, Mabel Pines, goes off to live with their uncle Stan and Ford. They been there since they were kids so it was like a normal thing but this time, it was permanent.
Their parents died in a car accident. Mabel decide that they are both gonna live in Gravity Falls. It was the summer and it's a great time to go since they go every year.
Dipper and Mabel are finally 18. The year they are gonna graduate. Before that, Dipper finds out that Mabel became friends with a triangle.
Mabel made a bet. A bet that could be true.