Authors note: disclaimer I don't own gravity Falls only the plot. Also there may be ties to Greek and Norse mythology enjoy :) (p.s I'm British)
Dipper and Mable pines were heading home to piedmont California on a speedy beaver bus. Dipper was just dosing off when a parcel hit him on the head. No one was on the bus except him, Mable and the bus driver. On it said "DiPpEr" in a three year olds writing. He hesitantly opened it. What was inside was: three blue hardcover books, invisible ink, a ultraviolet light, pens pencils, sheets of gold card paper. But the surprising thing was the copied pages of journals 1,2 and 3...
QFB FGAB YBFGKA TXZFBP
Hint : kcab srettel eerht