When Hiccup discovers Toothless isn't the only Night Fury, he must seek "The Hidden World", a secret Dragon Utopia before a hired tyrant named Grimmel finds it first.

Tony Towers is a local celebrity, a successful nightclub manager and he is engaged to a younger woman, Sue. Things get a little strange when he embarks upon the 3:17 to Nottingham for a Christmas family reunion.

In Barcelona, secret agent Antoine Donadieu thwarts the plans of a Nazi scientist.