(PG) ****

Director: Dean DeBlois.

Cast: (voices) Jay Baruchel, Cate Blanchett, Gerard Butler, America Ferrera, Djimon Hounsou, Craig Ferguson.

IN How To Train Your Dragon, DreamWorks Animation hit a home run, unleashing one of their finest films to date.

With its smart script, strong themes, and a delivery that was never dumbed-down, writer/director Dean DeBlois delivered the studio their best-reviewed CG film to date - better even than Shrek and Kung Fu Panda. 

Following up such a success can be hard to do, but DeBlois' powers haven't diminished. In fact, he dares to go deeper, smarter and even darker, honing in on the elements that made the first film work while expanding the world it's set in. 

Once again focusing on our differently abled heroes, Hiccup and his dragon Toothless (both are missing body parts), the sequel picks up five years on from the original to find the Viking villagers of Berk living in perfect harmony with their dragons. 

Everything is idyllic, except Hiccup (Baruchel) is not enamoured with the idea of succeeding his father Stoick (Butler) as chief of Berk. Hiccup would rather be out exploring the world with Toothless and mapping new territories.

But a chance encounter with dragon trappers leads Hiccup to the realisation not all the world is at peace with dragons, putting him in further conflict his father and leading him to the film's big bad, the scar-faced Drago Bloodfist (Hounsou).

DeBlois has been touting this film in interviews as the Empire Strikes Back of his planned trilogy and for once it's not hyperbole or over-ambition - this is indeed the darker film, complete with the bittersweet end-note (Hiccup also brandishes something not unlike a lightsaber and we are introduced to a "light side" and "dark side" of dragoneering).

While its bloodless violence and dragon-on-dragon warfare still keeps things to a family-friendly level, the sequel is not afraid to push things with some moments - the emotional peak at the end of the second act is genuinely surprising and affecting. On top of that Bloodfist is probably the most terrifying CG film villain seen for a while (and sure to be the impetus for some questioning along the lines of "why is the movie's lone black character the bad guy?"). 

The sequel is far from perfect but, as with its predecessor, the flaws get overwhelmed by the heart and the smarts. DeBlois is not afraid to spend time building up certain characters and their relationships, but the editing is good enough to pick things up again when it feels like the quiet moments have dragged on too long.

There are some good laughs along the way, but this is an intriguingly serious affair (aside from the odd flying sheep) that should prove rewarding and engaging for all ages.