The army of the dead has arrived at Winterfell and Game of Thrones season 8, episode 2 has revealed the Night King's plan to kill Brandon Stark - but where is the Night King? The episode ended with the chilling sight of the White Walkers gathering at the front of a devastatingly enormous army of wights, but the original White Walker and the leader of the army was conspicuous in his absence.
As Jon Snow laid out grimly, the living do not have the sheer numbers required to defeat the White Walkers' army, and face a hopeless battle even with Daenerys' dragons on their side. However, it's believed that since the Night King made the wights and controls them, killing him will stop them in their tracks, as they're basically just drones to his queen bee. The challenge is one of drawing the Night King out in the first place, so Bran suggested that he be used as bait, waiting in Winterfell's godswood.
The leader of the undead army is an enigmatic villain whose motivations aren't always entirely clear, but this episode laid them out in as much detail as we need. The Night King plans to bring about an eternal night, wiping out mankind altogether, and in order to accomplish that he needs to kill Bran - the Three-Eyed Raven. As Sam points out, true death is only achieved when people are completely forgotten by the living, and the Three-Eyed Raven has access to all of human history, making him a crucial target for the Night King. But if the Night King's plan is to kill Bran during the Battle of Winterfell... where is he?
The Night King cuts a particularly conspicuous figure now that his mount is none other than the resurrected Viserion, an enormous ice dragon powerful enough to take down the Wall. But while the end of the episode showed a lineup of White Walkers on undead horses, none of them was the distinctive Night King, who has spikes on his head forming a crown. There's also no sign yet of Viserion. In a show where the leaders of armies commonly ride in the vanguard (except for Joffrey, who preferred to run back to his room and hide during the Battle of the Blackwater), it's unusual for an army's leader to be nowhere in sight as the start of a battle nears.
One obvious explanation for this is that the Night King is deliberately hanging back, knowing that he's the queen bee and that his death would be the undoing of the entire wight army. It may take effort on Bran's part to draw the ancient creature out and bring him to the heart of Winterfell so that he can be killed. If that's the case, then the Night King could be lurking at the rear of the army that we see at the end of the episode.
There is another, more ominous possibility, however: that the Night King isn't at Winterfell at all. Some fans have speculated that he might plan to use the Battle of Winterfell as a diversion while he launches an attack elsewhere in Westeros, since the Night King now has a dragon and can fly anywhere relatively quickly. He may even have gone ahead to attack King's Landing while its defenses are down. That would certainly give Queen Cersei a bit of a shock.