There are two types of ponies in the world: dog ponies, and cat ponies.

Anyone with two eyes in their head could easily determine which categories both Applejack and Rarity fit in. But, when Rarity must take a last minute business trip to Manehattan, it falls on Applejack to take care of Rarity's beloved pet, Opalescence.

The problem is, Opalescence doesn't like Applejack.

Opalescence doesn't like anybody.