The first LotV Mission
Beware, spoilers be ahead, kinda. Not much in the first mission apparently:
https://www.youtube.com/watch?v=sym7D-egfo8
(This is a youtube video from a Eurogamer piece. You can find the article here: http://www.eurogamer.net/articles/2015-10-16-watch-the-first-mission-from-starcraft-2-legacy-of-the-void)