An older glimpse of the two main characters from How To Train Your Dragon.
Dreamworks has a nice franchise on their hands, even though each film suffers from huge unexplained plot holes.
My prediction for the 3rd HTTYD film: Astrid has a child, Hiccup finds new land, Toothless finds more of his kind, there will be a talking dragon, Valka dies, Drago does not return but dies if he does, some exterior people interfere (witches, pirates?), and there will be a major plot hole in the ending.
But not enough for the movie to be ruined.