A/N: Greeting and Salutations everybody! This is my very first non-personal fanfic so I do not guarantee that it will be the best quality but I am hoping to improve so please leave constructive criticism and let me know if there are any inconsistencies with the show (I have watched a lot of the episodes but I am no expert!). Please enjoy the story!
It was a fairly normal day for Dipper and Mabel Pines, as normal as it could get when you where in Gravity Falls. Dipper was sitting outside reading the journal and Mabel was playing with Waddles when a black car drove into the Mystery Shack's parking lot. As Dipper was about to go get gruncle Stan out of his recliner he noticed that no one exited the car except a tall brunette in a suit and dark sunglasses . The tall woman walked over to the twins.
"Hey kids, I'm looking for Stanford Pines is he here?"
Mabel smiled
"He's in..." she started but Dippers hand shot over her mouth
"He's in town, we're not sure when he's coming back." Dipper said hastily.
The brunette raised her eyebrows
"Oh, alright I'll just wait for him inside the mystery shack then."
After the woman walked into the shack the door shutting behind her Mabel turned and frowned
"Dipper you know gruncle Stan is napping in the house."
"Mabel, come on does she look like a tourist to you? What if she's a tax collector?"
Mabel gasped
"You're right , we have to warn gruncle Stan!" Mabel said
"Mabel, we can't warn him! She's in the shack!"
"Nuts!" Mabel said snapping her fingers
"We'll just have to wear her to the point where she leaves!" Dipper said.
Mabel grinned "Perfect!" she gave him a high-five and then walked into the Shack.
The woman was inspecting the beavercorn her sun glasses were off and her green eyes were staring at intently
"Hi" Mabel said sliding up to her making the woman jump to the side a little
"Hi" the woman said with a hint of amusement but looking at her with mild suspicion.
"What's your name" Mabel said grinning up at her
"Uhh it's Katarina." she said moving to the next oddity glancing at Mabel uncomfortably.
"Catalina? Like the dressing" Dipper said coming up to them
"What? No, it's KataRINA" she said
"OH." Dipper said awkwardly looking away.
"So what are you two's names?" Katarina said wandering over to the Sascrotch exhibit shaking her head after glancing at the sign muttering "wow." sarcastically under her breath.
"I'm Dipper Pines and this is my sister Mabel." Dipper said.
Katarina nodded "Hmm I thought so" she said moving into the gift shop
"What do you mean you thought so?" Mabel asked as she and Dipper ran to catch up to her
"Eh you two just have the Pines look to you." Katarina said looking around the room.
Katarina then turned and knelt to Dipper and Mabel's height
"Alright, I understand that you two are just trying to protect Stan but I really need you to tell me where he is because I really need to talk to him about something important."
"Dipper already told you he's in town." Mabel said.
Katarina took a deep inhale through her nose
"Fine." she said calmly with a hint of frustration in her voice and in the way she stood up.
As she stood up Soos walked in through the gift shop entrance
"Hey guys, I was wondering..." he started but was cut off as Katarina flipped around
"Do you know where Stan is?" she said.
Soos stared wide-eyed
"I, uh umm I uh..." he stammered and then slid out the door again.
"Ugh typical," she grumbled she then turned back to the twins
"I was trying to be polite before but now I give up. I'm going inside to go find him myself."
she then made a bee line for the door to Stan's house.
"NO!" Mabel and Dipper shouted in unison jumping on her causing her to fall to the ground.
"CRIPES! What is wrong with you two!" Katarina said trying to shake them off as gently as she could.
As Katarina finished the last syllable of 'two' the door to the house open and there stood a yawning gruncle Stan
"Mabel, Dipper... haahh... what's all the ruckus abo...," at this point Stan had opened his eyes after finishing his yawn to see Mabel and Dipper each clinging to one of Katarina's legs
"Katarina?!" he said in surprise.
"You know dad," she said finally shaking Dipper and Mabel off standing up
"I think next time I come to visit you, you should tell people 'Hey I have a daughter and she's coming to visit' so they don't think I'm a goon from the IRS and attack me!"
"Dad?" Mabel said looking at Dipper confused
"Daughter?" Dipper said looking back at her equally perplexed.
They both then turned to look at gruncle Stan and his supposed daughter Katarina and summed up their confusion in one word said in unison
"What?"