Replying...
Intro. (It's an Omegaverse! Then I make a version without being ABO!) Alphas of the universe: Bill, Mabel, Stanford, Stanley, Soos, Robbie and etc Betas: Grenda, Mcguckt, Candy, Wendy and etc Omegas; Peaceful, Dipper, Soos' girlfriend and etc ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Where Dipper and Mabel return to Gravity Falls both at 18 years old (In an Abo world, where Dipper is an omega and Mabel an alpha), Dipper is more reserved and cold than he was years ago, and Mabel is still cheerful and silly... But Dipper has become colder and more reserved, because everyone practically ignores him, bullied him, besides him he was never really loved, since everyone preferred Mabel and Mabel only thought about her, even if it was unconsciously hers... In this, Dipper ends up going to the forest, going where the statue of Bill Spoon was, Dipper ends up releasing Bill, and making a contract with him, now being Bill's ally... Dipper being extremely intelligent, could help Bill a lot who now had a human version of himself..

Billdip - A summer with a new villain or two.. (Omegaverse)

@Felix