***THEORY SPOILERS ABOUND! YE BE WARNED***
Indeed, Sir William. Currently some of the running assumptions for what exactly will happen after said blanket party is either Melisandra will use her special Red God Powers to bring him back (Using basically the power Thoros has been using on Beric Dondarrion to bring him back), or that he might even potentially come back as a sentient Wight, which would really add to the 'Ice' part of the 'Song of Ice and Fire.'
Personally, after watching the show as well, and seeing the emphasis that's been placed on the power 'Royal Blood' has with the workings of the Red Priests, it could well be she could use all of the blood spilled to make some major magical feat occur as well. I didn't recall quite as heavy of a 'Royal blood is uber important, look what I can do' being stressed as heavily in the books, but I'm due to take another lap of the published 5 here soon, and I may be mistaken.