|Avoid clicking to avoid spoilers!|
And I forgot to mention the air date! Looks like part one of the season finale will be on April 21st, according to this little snippet.
Have the actual synopsis after the break in text form!
Thanks to Alex for the image!
"Not everything is rainbows and gumdrops in this two-part special that finds unicorn Twilight Sparkle digging up a wedding shocker as her brother Shining Armor prepares to get hitched. -MWB"
Twilight Sparkle has a brother?! Madness!
Someone pointed this out in the comments, his mark is pretty much the same as Twilight's, with a shield.