DanialRizqin
A continuation of Season 2, and closely follows the lore of Gravity Falls, based on the Book Of Bill & Journal 3, as well as the information from r/Gravity falls.
"Arguments continued, louder and louder. Each night, a nightmare. Something, or someone, is trying to contact him in his mind, but all he could hear was gibberish and ciphered phrases.
Soon enough, just a couple of weeks after returning to Piedmont, Mason Dipper Pines returned to Gravity Falls, leaving behind his twin sister, Mabel Pines, to face the family problems. Not wanting to face and suffer through her parents arguments, Mabel Pines had to move to Los Angeles, California, to stay with her grandfather, Shermie Pines.
Times passed, and 4 years flew by. Now almost 16, Summer break arrived, and finally after some discussion, she is returning to Gravity Falls with her grandfather.
During that 4 years, much changed. Her new classmates bully her while people rarely hang out with her. Communication? Only a necessity. Her brother? Rarely talks. From a weekly conversation on the phone, to just... none. That affected Mabel greatly. She isn't the brightly cheerful twin girl of the family anymore, but now a teen who hates life. Bored, miserable.
Shermie sees this, and he wants to help her niece, and also see his brother... well brothers. He got news that Stanley is still alive! He also wants to see his nephew, Mason. It's been quite a while.
At the Mystery Shack, she met her grunkles after what felt like an eternity, and at last, her long forgotten brother. Dreadful and hateful thoughts flood her mind, and she really wants to kill-
Nevermind all of that. Now all that Mabel needs to go is to go through the next 2-3 months of Summer break. What's the worst that can happen?"