Sol, a Changeling, not a very bright one at that, decides to go explore the pony capital of Canterlot for the day, but since the Changeling Hive are planning on taking Canterlot for all the love ponies have, he will have to go in disguise. Doesn't help that his shape shifting doesn't seem to be working. Nor does it help that today of all days is actually the Royal Wedding between Cadence and Shining Armor, the day planned for the assault..
But still, Shit happens sometimes..