[Jack starts toward the edge of town.]

I'll show you.

[The trek was very long but the fog can be seen clearly at the end of the road.]

That fog.

[The wall of white seemed to create a dome around them as far as the eye could see that stretched up to the sky.]

That fog and what's beyond it are yet to be known.

[He's not going to entirely say how he knows that leaving town isn't possible just yet.]