[He looks back at her, and his distant gaze focuses.]

The Wall will hold the Dead for a time. But what I saw at Hardhome, when they fell on us from nowhere... tens of thousands of men, and women, and children, all slaughtered, all made to march for him. He made a point of letting me see them all rise. He’ll do the same again, whenever he can, wherever he can.

[And, he implies, he won’t stop at the Neck as a courtesy to southron rulers who think of the Dead as a Northern problem, or, more likely, a story to frighten unruly children.]

I don’t know how long we have. What I came for... what I was going for... was your aid. We will make our stand at Winterfell, but we don’t have enough dragonglass, enough Valyrian steel. There’s no help for the Valyrian steel, but there’s a cave on Dragonstone. A book in the Citadel says it’s full of dragonglass. Some call it obsidian.

So aye, it is why I was sailing to meet with you. That, and Lord Tyrion’s invitation, his thought that our interests align.

Why did he think to invite me? He didn’t tell you that he’d lie to me.