Rarity has a dress shop, and for the longest time, she dreams of making it big in the fashion industry. However, Sweetie Bell living with Rarity on a more permanent basis has forced the unicorn to accept that she is learning just as much about the fashion world as she is about rearing fillies.

So when her little sister comes home one day and asks a most disturbing question regarding their unicorn parents, Rarity is intent on busting what she believes is a myth that has so long lingered regarding unicorns. After all, there was no need for everyone in Ponyville to think that unicorns commonly commit acts of incest when such was not true.

Right?