Ponyville knows that Rainbow Dash and Vinyl Scratch are ultimate lovers of pranks and fun times galore, their passion for it rivaling Pinkie's. The two of them alone could cause damage as is. But together? There would never be a good outcome for what they do. Now the two have decided to give Derpy stolen, experimented muffins, and the goofy mailmare started acting weird. Even weirder than usual. Now, they need the help of the other ponies to fix the terrible mistake that they made.