Sorry it took a while to update, I was very busy. I'm sorry if Gideon's a little out of character, it was hard to find the right dialogue for him. Enjoy!

Brain landed on his belly. He got up and brushed himself off, only for Pinky to land on top of him.

"Gee, Brain," said Pinky, getting off of Brain. "Where are we? Narf!"

"It appears that the portal has sent us to Gravity Falls, Oregon. Of course, it makes perfect sense!"

"Why, Brain?"

"Because, Pinky, this is the place where dangerous mysteries and creatures are born! If we control Gravity Falls, we can use their resources to take over the world!"

They looked around and realized the atmosphere around them was different from the rest of Gravity Falls. The sky was not blue, but covered in grey, murky clouds instead. Fog covered the ground, and Pinky and the Brain found themselves standing in front of a big, black building. Brain saw a sign next to him that read Gravity Falls Maximum Security Prison.

"Come, Pinky. I think the portal sent us to this specific area for a reason."

They walked around outside of the prison until they found a window. It was a hole in the wall with bars on it, preventing whoever was inside from escaping. Pinky and the Brain managed to climb up the walls and see through the window. There, a little boy wearing an orange jumpsuit and a hair net over his poofy white hair was sitting down, bouncing a ball off the walls, and talking to himself.

"As soon as I get out of here the Pines family'll wish they never met widdle ol' me!" he muttered.

This gave Brain an idea. Maybe the boy was just what the pair needed.

"Pinky," said Brain, "are you pondering what I'm pondering?"

"Um, I think so, Brain. But how can Little Bo Peep be sure that her sheep will come home?"

"Don't make me hurt you, Pinky."

"Sorry, Brain. Poit."

Brain turned to the boy.

"Hello," said Brain.

"Huh, what? Where?" said the boy, standing up and looking around the room.

"Up here," said Brain. "By the window."

The boy saw them and screamed, cowering against the wall.

"I've been in jail for too long!"

"I can reassure you that you are not hallucinating," said Brain. "My name is Brain. This is my partner, Pinky."

"Zort!"

"Who are you?"

"Gideon," said the boy. "Lil' Gideon Gleeful. Why are y'all here?"

"We are laboratory mice trying to take over the world," said Brain. "I want you to help us."

Gideon chuckled.

"What's in it for widdle ol' me?"

"We'll help you escape from jail if you agree to help us take over Gravity Falls," said Brain.

Gideon thought to himself for a while.

This is it! I'll finally have my chance to get revenge on the Pines family and destroy them for good!

"I'll do it!"

"Yay!" said Pinky. "Narf!"

The mice jumped inside Gideon's cell and landed in his hair.

"Egad, Gideon!" said Pinky. "Your hair is so roomy!"

He petted it.

"Why, thank you!" said Gideon. "Now, how are you gonna bust me out of here?"

"Simple, Gideon," said Brain. "I shall use my tail to pick at the lock."

"Are you sure it's gonna work?" said Gideon.

"Of course," said Brain. "I have had years of experience at this. Don't question me."

Gideon lifted Brain up to the top of his door, which had a tiny window on it. Brain crawled through it and jumped off, grabbing the lock so he wouldn't hit the ground. He used his tail to pick at it, unlocking the door in two seconds. He opened the door and Gideon walked out with Pinky in his hair.

"Splendid job, Brain!" said Pinky.

Alarms went off and red lights flashed everywhere. Gideon picked up Brain and put him in his hair as the three of them were being chased by five security guards.

"Faster, Gideon!" said Brain. "Don't let them catch us!"

Gideon ran as fast as he could, running through hallways and corners that seemed to last forever. Finally, he made it to the door and escaped jail with Pinky and the Brain.

"Where are we going now?" said Pinky. "Narf!"

"I know a place where they'll never find us," said Gideon.

They arrived at Gideon's house, where the Tent of Telepathy was in ruins. Gideon broke down the door and entered the house where his father, Bud Gleeful, was sitting on the couch and watching TV. He was surprised to see his son.

"Widdle ol' me is finally back!"