Two months after Pacifica runs away from Dipper and the portal project, Mabel appears at Dipper’s house. She’s gotten really concerned, because her idiot brother has stopped responding to any letters, stopped picking up phone calls, stopped publishing articles, and has more or less completely dropped off the goddamn map.
So she arrives in Gravity Falls, locates her brother after a waitress mentions the “weird smelly researcher living in a hut in the woods,” and nearly takes out his front door with her knocking before he finally answers the door.
He is holding a gun.
Mabel is unimpressed.
She tells him to cut the shit and answer her already, what the hell is going on, why has he not been answering her letters, why is he living in a shack in the woods in Oregon, has he showered in the past two weeks?
Unfortunately for Mabel, Dipper is not in the right state to answer her questions reasonably, because he has well and truly lost his goddamn mind after Pacifica left him. Hosting Bill has been horrible for his mental state - Bill hasn’t been even a little bit gentle with his brain, even less so than he was with Ford in Canon Falls, and Dipper is Feeling It.
After Pacifica left, Dipper has been running on dwindling money, materials, and equipment. He’s at his limit. Bill is pushing him past it.
In response to Mabel’s reasonable questions, i.e “wtf is going on with you”, Dipper goes I’M UNCOVERING THE SECRETS TO THE UNIVERSE while waving his gun around and making a lot of concerning facial expressions. It’s concerning. Mabel is concerned. She does manage to take his gun away, though.
Mabel and Dipper have an argument, the main points of which can be boiled down to:
Mabel, freaked out: Dipper, I think you might be actually genuinely insane right now. Please go take a bath, you smell horrible.
Dipper, eyes bloodshot, waving his hands around: I NEED TO BUILD A PORTAL TO ANOTHER DIMENSION FOR THE GLORY OF THE TRIANGLE AND TO PROPEL MYSELF INTO FAME AND FORTUNE
[Dipper drags Mabel downstairs into his basement and triumphantly shows her the newly-finished portal]
Mabel, was not expecting an actual literal fucking portal: What the hell is GOING ON with you
Dipper, suddenly furious: You wouldn’t understand, you always were the more popular twin, you’re the successful famous rich amazing popular etc etc tw
(Mabel internal dialogue: exCUSE ME?)
Mabel's like, pretty sure that her brother is actually going insane, but he's still saying some really hurtful things, enough so that she starts to get pissed at him.
Mabel notices that Dipper has been holding onto a journal (...the journal she made for him?) this entire time, so she yanks it out of his hands and tells him that he's coming upstairs right now, he's eating a goddamn meal and drinking a glass of Mabel Juice and getting ten hours of sleep and then after that, maybe, they can have a reasonable and adult discussion about whatever the hell is going on with him.
Dipper says something Very Sane and Comprehensible, at a Reasonable Tone and Pitch, at the thought of sleeping for so long (THE DEMON). Then he lunges for the journal.
They... fight. There's a huge commotion. Dipper is screaming.
(For the first time, Mabel is scared, not for, but of her brother.)
Levers get pulled. Mabel's arm gets scorched when Dipper pushes her into a hot rune. She shrieks. His eyes momentarily clear, and he says "Oh god, Mabel, what have I-"
She kicks him off of her.
Dipper goes through the portal. The portal screeches to a close.
Mabel sits in the basement, burned, clutching her brother’s journal, and begins to panic.
When everyone blames Mabel for weirdmaggedon happening.
First of all no, she’s a child who is dealing with a really big change in her life and has felt more isolated and anxious as the day went on. She kept getting more and more hopeless about her birthday being alone and going back home without the one constant in her life -> dipper. She’s at one if not THE lowest moment for her character we see in the entire show.
Of course I wouldn’t blame her for being tricked and manipulated by bill, who of course chose to take advantage of her in the isolated and depressed state in the middle of the woods.
But you know what else? No one told her about the rift.
If anything, this is all ford’s fault.
If he didn’t insist on being so secretive and isolated (yes, some as a trauma response from his childhood & also the toxic relationship w bill) then he shouldn’t have told dipper to do so, too.
At the end of that d&d&d episode, ford shows dipper the rift. He briefly explains how if broken or given to bill, it will start weirdmaggedon.
And you know what else he told him????
To keep it a secret.
That’s right. To not tell anyone. “trust no one.”
Not. Even. Mabel.
If ford wasn’t so adamant about not telling another soul besides dipper about the rift, then at the very least mabel wouldn’t have so easily given it over to bill.
At the very least, he probably would’ve had to take it from her, but she wouldn’t have given it up voluntarily IF SHE KNEW WHAT IT WAS.
(Which again, bill x ford’s toxic relationship really is the core of the show, from pre-s1 to ofc here in the finale).
