Pacifica and Gideon are in fact, your Allies. Mabel and Dipper are in fact, your Enemies.
Pacifica and Gideon explore to solve all the mysteries, with the Journal Pacifica occupies, they'll all solve it in no time. Solving the mystery of the TWINS, Mabel and Dipper, will they ever find a way to solve it?
(Original series at TV = Gravity Falls, Reverse Falls idea wasnt originally MY idea. Im just making a fan fiction. Enjoy!)
Edit: Cover not mine