Pinkie eating Celestia's cupcake didn't go down very well- at all. Now the Mane Six are down an element of harmony, and all of Equestria may be doomed! Or not. Luckily, Cheese Sandwich is there to save the day. But when Pinkie comes back, they may all learn how Pinkie Pie does what she does...
It's a completely ridiculous story, just meant for laughs, so don't take it too seriously!