For Daenerys and the Night King already to meet face-to-face on the battlefield is a hugely significant and exciting moment, and one that marks a major turning point for this show. (More on that in a bit.) In many ways, the biggest surprise of this episode wasn't even the death and resurrection of the now-undead Viserion, but rather that any of this even happened at this stage in the story. These are pretty major developments for any season of Game of Thrones, let alone a single episode - and we haven't even gotten to the Sansa/Arya/Littlefinger storyline. No wonder he so readily bowed a knee to Daenerys. Presumably all one has to do is kill all the White Walkers in the army, and the rest of the creatures (or at least the majority of them) will come down after. "Beyond the Wall" also gave Jon Snow his first real glimpse of how he can defeat the Night King and his army: We seemingly learn that by killing a White Walker, you can knock out all the wights he created. We haven't seen Daenerys truly afraid in a while, but she deserves to be at this juncture. More significantly, Daenerys saw the threat of the undead herself and realized the Night King is the true enemy. Despite the major loss, Jon and his band of merry men did get the wight they needed to convince Cersei this threat is real. Heck, he might be able to fly over or around the Wall just like Daenerys did, though that wouldn’t help him get his army of wights into Westeros any faster. To lose Viserion is a major blow, but to have the Night King resurrect Viserion and add it to his ever-growing army of wights, giants and bears is an even bigger threat. Cersei Lannister might not have had the means to kill a dragon two episodes ago, but it turns out the Night King had a slightly more impactful Scorpion-like bolt in his arsenal (and slightly better aim than Bronn). It's something her Hand, Tyrion, has repeatedly criticized, and though he could have found a slightly more tactful way to bring up who would succeed her should she die, "Beyond the Wall" proved it was a prescient question. That loss is one of the most game-changing moments in Game of Thrones to date, and hopefully will be a good wake up call for the dragon queen, who has, until now, been acting as though she’s invulnerable.