I believe it is no secret that episode 3 will be the siege of Winterfell, with what the show guys describe as the "biggest battle sequence on film", "longer than Helm's Deep", etc.
That probably leads to one of the following:
-The Night King utterly defeats the North, then proceeds south and easily defeats Cersei's forces (or is maybe easily defeated by her, 'cause don't you know, she employs the Golden Company, secretly led by the bastard Aegon, who's actually Azor Ahai
!). Unlikely, but actually not a bad scenario for me, as we can even get undead Hound vs zombie Mountain, along with all the other heroes the masses wanna see throw down with Cersei (not-dead-fake-Aegon-true-Azor-Ahai vs undead-true-Aegon-fake-Prince-That-Was-Promised, anyone? No? Okay...).
-North utterly defeats the White Walkers, then their remnants get into a lesser conflict with Cersei. I fear this is one of the likeliest scenarios, but it would cheapen the threat of the Walkers for me (and the show as a whole, as such). Building the menace of dem undeadies since day 1 to just dispatch of them when they make their first real move and then return to the same old soap squabbles?
-North is defeated, but they manage some sort of retreat, so the final battle is King's Landing or some other place where Cersei has no choice but to join them (like, her forces coulda been out to meet them on the way down, but the infighting halts as the NK catches up). It might seem improbable, given that we know the biggest fight will be in episode 3, but maybe the point of that fight was to show that no force of arms can keep dem deads dead, so it's kinda like the end of LOTR, where all remaining forces go into a hopeless battle that diverts from a more strategic attempt directed at the NK himself.
-The North prevails, but the NK is not vanquished and resurfaces below their lines, forcing them to march down as well. Could be interesting, but mostly if da King ends up with an undead Queen army, which I do not think particularly probable...
What say you?
Drax the Legend, Captain of the Fist, The Starwalker, The Jade Slayer