SPOILER ALERT! This video contains spoilers about 5.1, Thrall, Vol'Jin, you name it, if it's Horde lore, there's spoilers in this video. Watch at your own risk.
That aside, it's pretty interesting stuff. There are definite plot advancements taking place, and it's all very interesting if temporally rather troubling!
The return of Thrall, as incumbent Warchief, has to be a worry for Garrosh and his cronies. The footage is taken from one of the quest lines for the new Dominance Offensive faction. The new faction, and its Alliance sister, Operation: Shieldwall, are the result of the eventual arrival of Horde and Alliance ships dispatched by the relevant leaders from the relevant faction capitals. As the story goes, the Horde ships landed at the Alliance end of Pandaria, while the Alliance ships made an equal, yet opposite, error. Both factions wish to secure Pandaria as their own, and by carrying out quests for the two factions players can aid Garrosh and Varian in their quests to paint the new continent red or blue.
More spoilers after the break!
Most notably, the first thing many will take away from the video is that upon arrival in Thrall's little camp, there's something next to a lady orc who's crouching on the ground. That lady is Aggra, and the thing next to her appears to be a crib. Now, given that Anne Stickney, one of our resident lore gurus, tells me we've only been in Pandaria for two months, that is one heck of a short gestation period.
Vol'Jin is seriously injured, as is hinted at in earlier datamined scenario audio, and Chen Stormstout has decided that the best remedy for an injured troll is handfuls of needles. Vol'Jin sends you off on a quest to find Thrall, giving you his hearthstone to aid you. This takes you to Thrall in southern Durotar. After a journey, it transpires that the Kor'Kron have taken over Echo Isles, at a new Warchief's behest, and no longer answer to Thrall...
Mists of Pandaria is here! The level cap has been raised to 90, many players have returned to Azeroth, and pet battles are taking the world by storm. Keep an eye out for all of the latest news, and check out our comprehensive guide to Mists of Pandaria for everything you'll ever need to know.