Twilight was exploring the Castle of The Two Sisters, when she finds a mysterious portal. Twilight believes Celestia would know, but she doesn't! Where will this portal lead Twilight and Pinkie? There are too many Genres to fit in the two Genre slots, so I'll list them all! Adventure, Fantasy, Romance, Humor (I think). Oh, wait, that's not much... oh well. Enjoy!
Crossover - My Little Pony & Gravity Falls - Rated: K+ - English - Adventure/Fantasy - Chapters: 17 - Words: 7,890 - Reviews: 42 - Favs: 23 - Follows: 25 - Updated: 9/24/2017 - Published: 6/2/2015 - Twilight Sparkle, Pinkie Pie, Dipper P., Mabel P.