This is maybe for me (along with the odd incapacity of the Tyrells to mount any sort of reasonable defense of their home castle) the biggest plot hole in the show so far. I hope we’re going to find out what the Night King and Co. have been doing or waiting for soon, because they’ve taken a whole lotta time since Hardhome to get to the wall considering they didn’t seem so slow to move around during that particular battle.

If it turns out they’ve just been waiting for Dany to arrive with her dragons and the rest of Westeros to get their act together band against them it’ll be a bit weak.