Obsessive, compulsive, germophobic, but also a complete GENIUS, Adrian Monk, San Francisco's "Defective Detective" begins the most unusual case of his entire life!
In an alternate timeline, somepony else got to the Mirror Portal before Sunset and stole both it and Celestia away. Acting Princess Cadance is willing to give Sunset a second chance, and hopes to have Sunset's help with a matter of national security.
Adagio adopts the Apple family following their parents' deaths. What starts as a selfish plan for willing minions goes a little differently than she had in mind.
Halfway through the Friendship Games, Twilight realizes exactly how powerful her pendant is and enlists a more magic-experienced person to be her co-scientist.
Turns out Rainbow Dash and Rarity are a married couple, and have been since before Twilight moved to Ponyville. Twilight never knew this. Hilarity ensues, as well as a few feels.