I've seen a few people asking for information about the quest. If you don't want to know about it, don't read further! I'm going to give a quick overview rather than going card-by-card, as I don't have it in front of me, but I really enjoyed the quest. I think four-player is the hardest, solo or two would be the sweet spot here.
The major mechanic involves getting spun off into individual staging areas similar to Foundations of Stone or The Breaking of the Fellowship. The twist here is that you get sent off on your own if "your" player card is a certain type of Barrow.
[bIG SPOILER] When you get spun out on your own, you have to discard all allies except X, where X is the number of enemies engaged with you. This was a HUGE surprise, and as I was running a Gondor ally mustering deck, was quite the moment. To clear your own staging area, you have to quest 9 points worth, but any location revealed at your stage is canceled--you raise your threat by its threat cost instead. This, coupled with other threat raising mechanics, really puts the pressure on you throughout.
There are a few cool new effects on locations. Notably, one of them makes you defend Wights with your Willpower value while it is in the staging area. The enemies also have negative effects while engaged with you, like not letting you draw cards, produce resources, or the like. The enemies themselves are not super high stat wise.
All in all, a great flavor and a fun quest!