A/N: Diane Pines wanted to know what happened after The Rise of Grapple Girl.
And in case you're wondering, Randy and Howard are in the garage of Randy's house.

"He'll be fine," Mabel reassured. Then more colorful text appeared in front of her.

Are you done yet?

Randy STILL needs your help!

It's already been twenty minutes!

"Twenty minutes?" Mabel quietly asked. Then she looked over at Dipper. "I have to go."

Meanwhile, back in Norrisville, Randy was already getting worried. "I'm starting to think you made up this 'Grapple Girl' person," Howard said. "Waiting for her is taking up some valuable rehearsal time!"

"But she IS real," Randy insisted. "Just give her more time. She'll come."

As if on cue, Mabel showed up, decked out in her Grapple Girl ensemble. "Sorry I'm late," she said, gasping for breath. "There was a bit of a wormhole incident."

"THAT'S Grapple Girl?" Howard asked. "Your new sidekick is an eight-year-old girl!"

Mabel took off her mask. "I'm twelve," she said. "And my name is Mabel. You must be that Howard guy."

"How did you-?" Howard began.

"Dipper told me," Mabel said. "He said the Nomicon told me who you are when he was trying to weaken the Sorcerer."

"Wait, who's Dipper?" Howard asked.

"It's kind of a long story," Randy said. "Mabel, there's a killer robot-"

"Attacking the town?" Mabel asked. "The Nomicon told me." She put her mask back on. "I'm on it."

Mabel arrived at the crime scene, where a tall humanoid robot was rampaging. "Evil robot, your destruction is about to be terminated!" she cried out.

Back in Gravity Falls, Dipper was starting to get worried. Mabel was gone for a long time, and he didn't know where she went.

So while Dipper was in his room reading his book, he glanced at Mabel's side. Her outfit from today was laid out on her bed, and her grappling hook wasn't in its usual spot.

That meant only one thing...

Back in Norrisville, Randy and Howard were rehearsing new songs. However, Dipper ran into the garage and interrupted them. "Randy, where's Mabel?!"

"Dipper?" Randy asked. "What are you doing here?"

"Oh, so that's Dipper," Howard commented.

"Did Mabel come here?" Dipper asked Randy.

"The Nomicon sent her here," Randy explained. "I didn't want to skip out on band practice, so she's fighting a killer robot for me."

"WHAT?!" Dipper yelped.

Speaking of Mabel, she was having fun fighting the robot. After dodging a few attacks, she fired her grappling hook at the robot's legs. "Grapple Bind!" she called out, running around the robot in circles.

"I can't believe this!" Dipper exclaimed. "We haven't seen each other in two weeks, and you sent my sister out there to fight a robot! What is wrong with you?!"

CRASH!

Mabel came back to the garage. "That was too easy," she said. "Oh hey, Dipper."

"What did you do?!" Dipper asked.

"I pulled a Star Wars trick on the robot," Mabel explained, holding up her grappling hook.

"So, let me get this straight," Howard said. "You took down a huge robot with only a grappling hook."

Dipper then noticed Howard. "Wait, I know you," he said. "You were one of the guys I Destanked two weeks ago! Aren't you that Howard Weinerman guy?"

"Yes I am," Howard replied. "Don't remember seeing you, though."

"Again, long story," Randy said. "Point is, McFist sent me to an alternate world, and Dipper and Mabel helped me get back home."

"And you're okay with them knowing you're the ninja?" Howard asked.

"We didn't know until Randy told us," Mabel explained. "Our world is kind of different from this world."

"So, how did you two get here?" Howard asked.

In the forest, Dipper, Mabel, and Randy showed Howard the Transport Tree. "This is the Transport Tree," Dipper said. "It sends anyone to another world."

"That's so bruce!" Howard commented.

"But there's a problem," Randy continued. "Because of what happened two weeks ago, I can't go to Dipper and Mabel's, but they can visit me."

"Guess this means we'll be seeing a lot of you two," Howard told Dipper and Mabel.

"Mostly me," Mabel explained. "After all, I'm the Ninja's honorary sidekick."

"In other words, I won't NNS for a long time," Randy said.

"Won't what?" Dipper asked.

"It's short for Ninja No-Show," Howard explained. "Cunningham and I would do something awesome, but he would have to Ninja-out and fight a robot or monster."

"Oh, I get it," Mabel said. "With me as the sidekick, you two can still hang out while I fight the robot or monster!"

"Just give me a heads up when the Nomicon tells you Randy needs your help," Dipper said.

"Don't worry, Dippingsauce," Mabel said. "I will."