Diamond Tiara and Silver Spoon reckon that having money and power makes them superior to other ponies. They are also not very fond of blank flanks, and relish in making life a misery for anypony who is yet to find their calling.
So when they meet a blank flank unicorn filly from Canterlot who thinks that having money and power is not all it's cracked up to be, they begin to defend their own opinions.
Things only escalate from there, and the two of them end up getting more than they bargained for.