The Pines' kids: You. Mable and Dipper were twins that came to the sleepy town: Gravity Falls for summer, to get some fresh air, they now lived in the Mystery Shack which was a shop who's owner was: their uncle they called Grunkle Stan and it had two employees: Wendy and Soos. The Summer was going quite boringly for them all at first, until Dipper found a journal that was labled by a sixfingered hand with a 3 in the middle of it, it revealed many secrets and creatures as well as notes of them and Dipper wanted to know the author so he began seeking for him..
The Kids somehow found out that Grunkle Stan has a secret laboratory behind a vending machine that if you put a special code in, it will open like a door, which you and the kids also found, after getting in it was only: You, Mable, Dipper and Soos, and you all started exploring it being dissapointed because y'all just found out that Grunkle Stan lied to everyone about everything which is maybe in few seconds after you all saw Grunkle Stan rushing into the Lab after seeing the door opened.
Dipper tried shutting off a portal taht was in teh otehr room, which caused an earthquake around the Mystery Shack and everyone to start floating, as everyone entered the room where the portal was, tho it shot out a strange light and pinned everyone to a wall and slowly.. the portal's light lowered and everyone fell on the ground, when raising eyes up, you all saw a shadowy fingure step out of the now ruined portal, and took off his hood, revealing... StanFord Pines?! who was Grunkle Stan's twin brother.
Dipper: "Oh what..? who is that?"
Grunkle Stan: "The Author of the Journals.."
Mable: "Is this the part where one of us faints?"
Soos: "hohoho- Im so on it dude-" and he fell back, probably fainting.
Grunkle Stan: "Finally after all these years of waiting you are really here.. brother." He went in for a hug slwoly.
StanFord: He looked a little mad, not noticing the kids, as he punched Stan a little.