Happy Birthday ..Twins ? [Gravity Falls fanfiction AU]

Chapter 1

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Hi, so this is the first time i write a story online and i hope you will like it !
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No One POV

It was a beautiful morning in Gravity Falls, i mean more beautiful than usual, the nice breeze moving slowly the branches of the trees and the rising sun who shone on your skin.
Dipper and Mabel was walking through the forest not so far of the Shack, they were send outside by Stanley their Grunkle for secret 'bussiness' he had to do, even if Mabel and Dipper could already see they were going to make them a surprise party but they pretend like they know nothing for not to spoil the surprise.
Mabel let out a little laugh "what's so funny ?" Said her brother, "Nothing, i'm just excited. We're sixteen now Dipper aren't you excited to celebrate !?" Said Mabel happily jumping. Nothing changed  about Mabel these last few years when you saw her, she is still wearing sweater and still have a kink for glitter and stickers but wear jeans under her skirt now,"Yeah, i am but it's very difficult to be excited when you know that they are throwing a secret party", Dipper Pines, since the last time you saw him he grew like a beautiful young man, he became the alpha twin and grew more into books and mysteries but his character never changed, Dipper likes to wear hoodies with orange shirt under with jeans.
They continued to walk through the forest, laughing and speaking about everything they did amazing this summer until they stopped in front of a paper on the ground.
"Ooh ! Look Dipper ! A.. letter ?" Said Mabel.
"Strange, what's a letter doing here ?" Dipper said, Mabel look at her brother and raise her shoulders. Mabel took the letter and examine it, the envelope of the letter was white with a pink sticker in a heart shape on the middle, "It's a love letter ! It surely belongs to someone !" Said Mabel with excitiment while holding the letter in front of her "If it does we should find this person, plus the time will pass faster this way" Said Dipper, "Then let's go !" Mabel jump and throw a punch in the air while holding the letter in her other hand. "What was the jumping for ?" Dipper ask "Meh" Mabel raise her shoulders again.They started to walk at back at the Shack until mabel was trying to open the envelope, "Mabel !!" Scream Dipper, Mabel jumped by the sound of the voice "Oh come on ! It won't hurt anyone ! It's just a pick !" Said Mabel "But it's not yours, if the person see that we read her letter--" Befpre Dipper could finish Mabel cut out "I know~ But you know we can put in another envelop plus i have lots of stickers and i'm sure this 'Whoever this letter belongs to' won't know a thing !", Dipper knew that she was right, he kind of wanted to read the letter too, he stood there and think, "You right, i little pick won't hurt" Mabel grin grew widder by the excitiment of reading this 'Love letter'. They both look at the envelope. Mabel look at her brother and said "Care to open it ?", Dipper look at her sister and nod "you open it", Mabel grab the sticker on the envelope and took it of until a light comes out of it and start to sucks then inside, they both screamed "AAAAH--", the envelope close himself and dissapeared.
Stan opens the front door and looks around, "Hey Dexter ! Did you hear something ?", Ford walk back to see Stan while carying boxes in his hands "No ? Why ?", "No, maybe it's just my mind" after saying this Stan close the front door.

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Note: Hi ! Author here, i hope you enjoyed this first chapter and don't forget to leave a comment of what you think about this. If i did any mistake please make sure to tell me and i also take constructive critism ;)
Bye.
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