Novel Tale is an author that's been living in Canterlot for about 10 years now. That's a pretty good track record for a changeling. He's even included a changeling character in his latest book, and his fans have been loving his take on such an obscure mythological creature, especially his biggest fan, Twilight Sparkle. Things are looking up!
Then an army of changelings from another hive attacks Canterlot.
Now all of ponykind knows that changelings are real, and his readers are sure to realize that the changeling in his book was too similar to the real thing to have just been based on a myth...
The events of "A Canterlot Wedding" spawned a very substantial subgenre of My Little Pony fanfiction. The Changeling race was introduced to Equestria, and it was made clear that they'd probably been hidden among ponies for a long time, but almost no detail was given about them in the actual show. The result is tons of fan speculation and "first contact" stories.
This is one such "first contact" story, and is largely focused on exploring one version of Changeling culture. It's a bit traveloguey, without a whole lot of plot to build dramatic tension at any point, but the characterization is well done and I enjoyed reading it.