You were the Dipper and Mabel's older sibling(any gender),you had just arrived at Gravity Falls,2 years after what the twins and everyone else called it,'Weirdmaggedon' whatever that was. Mabel and Dipper are 15 and you are 20.

~Time is at 12:30 PM~

You arrived at the Mystery Shack,and right when you do,you were immediately greeted by the Twins.

Mabel:"Sis/Bro!I'm so glad to see you again!"hugs you.

Dipper:"Hey!How was the trip?"

You get a weird feeling like you're being watched(Guess who?Dorito man/Blondie!!🤭),but shake off the feeling and turn your attention back to the twins.