Warning! MAJOR SPOILERS for Game of Thrones season 8 ahead!
Filming is currently underway on Game of Thrones season 8 and invariably that means spoilers are leaking from the set. This spoiler, however, is a real doozy. Those who wish to remain in the dark about what may happen in Game of Thrones' final season should stop reading now. Seriously. The following information contains a HUGE SPOILER for upcoming events so do proceed with caution.
Today, Game of Thrones fansite, Watchers on The Wall, shared a video taken from outside the Winterfell set in Northern Ireland. Recent weeks have seen this set grow bigger, with more ramparts and towers getting physically constructed rather than being left for post-production CGI. It's been assumed this is because more action will take place at Winterfell in season 8 - specifically, a battle once the Night King and his army reach the castle - but thanks to this video we may now know why they really needed to beef up their Winterfell set - so it could be burned to the ground.
The video is short and not of the best quality, but what it depicts couldn't be any clearer - off in the distance is the very distinct silhouette Winterfell and its is engulfed in massive flames. This video is captured from a long way away, which means this is an incredibly large (and hopefully well-controlled) fire. A fire of this magnitude is not something that any structure - even a fortress as mighty as Winterfell - could be expected to withstand. So while it's impossible to ever fully confirm a spoiler until the episode actually airs, it sure appears as if Winterfell won't survive Game of Thrones season 8.
Of course, with any major spoiler comes only more questions. Who's burning Winterfell? What happened to those still inside? And when exactly does this occur? To the first question, there are really only two possibilities - it's either the Night King and wight-Viserion or Daenerys and/or Jon with Drogon and/or Rhaegal. Some serious fuel is needed to light a fire that big, so unless someone smuggled wildfire up north (which isn't really out the realm of possibility) then Winterfell is almost certainly burning with dragonfire.
The Night King reaching Winterfell and razing it with Viserion's blue flames (an effect added in post) seems to be the most likely scenario since his army is already marching south and Winterfell is sure to be one of his first stops. But then again, since fire is one of the only ways The Night King's army of the dead can be stopped, perhaps the Starks and their allies choose to sacrifice their ancestral home as a last ditch effort to destroy the White Walkers' forces.
If this bonfire is a result of The Night King's army reaching Winterfell, then it would seem that this happens early on in season 8; perhaps even the second or third episode. Then again, maybe humanity manages to make their final stand against the White Walkers at Winterfell, and this is then the result of that climactic battle, placing these events in the fifth or sixth episode. Either way, this castle is almost certainly done for, leaving those who called it home - most recently, Sansa, Arya, and Bran - to either die in its flames or escape and live to fight another day.
Game of Thrones season 8 will return in 2019 on HBO.
Source: Watchers on the Wall