TOOTHLESS/HICCUP hiccup is dying, and in an act of desperation, Toothless does something that will change them both forever.

Armin dreams of strange things: giant walls that tower fifty metres into the sky, protecting the cities inside from huge, man-eating creatures; the people that fight them, flying through the air. They wake him up screaming in the middle of the night, reaching for someone who isn't there. But he doesn't think much of them, until he realizes that they're so, so much more complicated.