"The Night King and the White Walkers have returned. These stories that Old Nan used to tell us? They turned out to be more than stories. Everything they kill, they raise from the dead to fight on their side. For the last couple of years, they have killed every living being north of the Wall, only to add them to their growing army. I only managed to save less than ten thousand Free Folk from Hardhome. The dead they raise we call wights. At this point, they have hundreds of thousands of them. Normal weapons don't harm them, but they are vulnerable to obsidian, fire and valyrian steel." He stopped, seeing that Sansa was looking at him with wide eyes. "Do you believe me?"