Applejack is called on yet another adventure with the rest of the Mane 6, but with Granny gone to see family and Big Mac dealing with things in Appleloosa, she doesn't know whop to trust to keep an eye on both the farm and Applebloom.
Luckily, Twilight was able to call in a favor by someone Humble and Apologetic.
That adult/nsfw tag is probably a typo, right?