"Grunkle Stan... I trust you," Mabel says, and lets go.
For one, endless moment, Stan is more surprised than relieved; her trust, in the face of all proof stacked against him and all the lies he's fed them, is undeserved at the very least. Then relief comes, and he has a couple of seconds to enjoy it. Three at most.
Then Mabel begins to float back towards the portal, and everything is drowned in unspeakable horror. He sees realization dawning on her face the same moment Dipper screams.
"Mabel! MABEL! NO!"
The noise that leaves Dipper sounds more like a frightened animal's screeching than a human voice, overpowering even the horrible noise coming from the machine, but Stan barely hears it: he can only stare, dumbfounded an unable to move, as Mabel keeps floating towards the portal.
This wasn't supposed to happen. This is wrong. Stanford should come out, he will, any moment now-!
"Dipper! Help me!"
Stanley! Help me!
Oh, no! What do I do?
"I... I don't know what to do!" Dipper cries out, trying and failing to move closer to her. But the force coming from the machine is overpowering, and keeps them all pinned against the wall. All of them except Mabel, whose attempts at grabbing onto something grow more and more frantic. She uselessly stretches her hand out, to her brother... but her eyes, wide and frightened, rest on him.
I trusted you, they tell him.
I don't know who I can trust, Stanford told him a lifetime ago.
"Grunkle Stan! Do something! GRUNKLE STAN!"
Stanley! Stanley, do something! STANLEY!
The scream that leaves him scorches his throat, and he manages to hold out a hand – but as always in his life it's too little, and too late. With one last scream and a flash of blinding light, Mabel disappears into the portal, gravity returns, and he falls.
The meeting with the floor is hard, and yet there is no pain; he's too number to feel anything, to even begin to process what happened, what he did, what he lost. He is aware, dimly, of his brother's machine crumbling before him. This cannot be, is all he can think as he lifts himself on his knees, it can't have happened, things can't have gone so wrong. She's not lost, she cannot be, she-
A high, keening noise breaks the sense of unreality. Stan turns to see Dipper kneeling in front of the collapsed portal, shaking and hunched over as though his body is crumpling from within. Something falls from his face, hidden by bangs of brown hair, to splash on the floor between his hands.
"She's gone," Dipper chokes out, and something in Stan's chest turns into lead. He tries to speak, but his ears are buzzing and his tongue feels too large. A lifetime feeding lies to everyone, and no he can't even allow himself the comfort of lying to himself.
Mabel is gone, lost like Stanford was, and there is nothing that will being either of them back. And it was his fault, because he activated the portal despite all warnings, didn't even think that he may be putting the kids in harm's way. He should have sent them back home, to be safe, when he first activated the machine.
But he hadn't, for the same reason why he was unable to be happy for the opportunity Stanford was given so many years ago. Because he wanted them, his family, to stay with him. Because he didn't want to be alone. Because in the end, he's only ever been a selfish bastard.
And now he's lost everything, again. Because Mabel trusted him, and he was wrong.
"Dipper..." Stan manages, his voice hoarse, but he doesn't get to say anything more.
"This is your fault. You lied!"
All you ever do is lie and cheat!
"You... you took her away. This is your fault. THIS IS YOUR FAULT!" Dipper screams, and finally looks up. Only that it isn't Dipper's face looking at him from beneath that mop of brown hair: staring at him, features contorted in fury, there's young Stanford. "You ruined our lives! YOU RUIN EVERYTHING!"
It was a mistake!
You ruined your own life!
"I... I didn't... I never...!" Stan stammers, and he stands, but the world spins around him and he loses his balance. He falls back, and falls and falls, the screams the only thing he can hear along with Mabel's own voice, distant and unbearably sad.
I trusted you.
Stanley Pines awakens with a cry, his right arm stretched out to the ceiling and his face wet. Sweat, he tells himself, and wipes it dry with the back of his hand before sitting up.
Reality is mercifully quick to settle in: there is no lingering doubt on whether what he just saw was real or not. It never happened, none of it. Stanford is back, regardless how bitter their reunion was, and neither of the twins was lost to the portal. They're fine, both of them, safe and sound in their beds.
But Stan knows he'll only be able to sleep after he's seen them with his own eyes.
Mabel is still wide awake, listening to Dipper's steady breathing and Waddles' soft grunts, when the door opens. The hinges have been oiled, so it doesn't creak so badly anymore, but the light coming from outside gives it away. She sits up, squinting against the light, to see a familiar outline on the doorway.
There is a slight grunt, and Stan - who was about to turn back and leave again, she realizes now - pauses. Still, he won't look at her.
"You should be sleeping, kid."
"Did you and Grunkle Ford hug it out?" she asks.
"... Don't think that's gonna happen anytime soon."
She knew what answer to expect, but it disappoints her nonetheless. She glances at Dipper's sleeping form, and the fear that's been gnawing at her gets suddenly worse.
You promise you won't get stupid?
"But later?" she insists, and she's not even sure for whose sake she's hoping for a positive answer. Either way, it's not the answer she gets.
"Don't hold your breath. Now sleep. We've got a tourist trap to run and-"
"I can't sleep."
She really didn't mean her voice to come out sounding so sad, but it still did, and Grunkle Stan stiffens. With a glance at Dipper - who's still asleep, their dad always says he could sleep through a hurricane and wake up the next day asking how's the weather - he finally steps in the room and sits on her bed.
Maybe it's because it's dark and he's so hunched over, staring at the floor like something heavy is pressing down on him, but right now he looks really, really old.
"... I'm sorry, kid."
Mabel doesn't know is it he's apologizing for, but the sorrow in his voice is more than she can bear. She reaches under her pillow, grabs her stickers, and jumps on her feet. Grunkle Stan yelps when she slaps a sparkly unicorn on his forehead.
"SPARKLY UNICORN POWER! Now you can't be sad," she announces, and is about to put another sticker on him for good measure, but she has no time to: the next moment Grunkle Stan has seized her, and then he's holding her tight enough to steal her breath.
"I'm sorry," he repeats, and for just a moment his voice shakes.
Well, fine. The sparkly unicorn clearly isn't enough, and if Grunkle Ford won't give him a hug, she will. He's missing out, anyway.
Mabel reaches up to wrap her arms around Stan's neck, and gives him the tightest hug she can manage. "You're still my favorite Grunkle," she whispers in his ear. "Just don't tell anyone."
She feels the rumble of his laugh more than she hears it. "Won't tell if you don't," he promises, and a hand leaves her back to ruffle her hair. "Now go to sleep before we wake up your-"
Both wince and look back towards the other bed, where Dipper is sitting up, hair still tousled and arms crossed. They can't see his expression clearly, and Mabel feels Stan tensing up some.
"... How long have you been awake?"
Dipper shrugs. "Since the Sparkly Unicorn battle cry," he says. He sounds so wonderfully normal that Mabel can't hold back a grin. She lifts an arm towards him, still on Stan's knees.
"There's room for one more! Come join the cuddle pile!"
Dipper rubs his chin, as if in deep thought. "Don't know. Maybe I'm too manly and tough to do that anymore."
"A manly man is not afraid of showing his soft side! Right, Grunkle Stan?"
Another laugh, and Grunkle Stan holds out one arm as well. "What she said, kid. Show me what you've got!"
Dipper's own hug is more like a tackle and it throws all of them back against the wall, but they're all laughing and Mabel is sure that Stan really, really doesn't mind.