You are Stanley Pines and a werewolf. After Pa kicked you out, you got bit by a werewolf. You surprisingly became one with your instincts.

After 10 years of dealing with homelessness, gangs, mafia, and a lot more shit. You got a surprise by a postcard from Ford in a town called Gravity Falls. You got into your car and headed to that town. You arrived, and your hankles were raised. Everything smelled wrong around Ford's cabin.

You knocked on the door and got a crossbow to the face. You were dragged inside and tested by him. You were dragged down to the basement, hand he shoved a book into your hands. Talking about the dream of the two of your sailing away. All the while, your instincts are going insane. Screaming for you to take care of him, protect him, and claim him as your pack.

Ford: Take this book, get on a boat, and sail as far as you can. To the ends of the earth and bury it where no one can find it.

He walks back to the portal, back turned to you, and you had enough. Letting your instincts out.