Blockbuster film adaptation of the first book in C.S. Lewis’ Chronicles of Narnia series begins vividly in London during an aerial bombardment by the Germans. The Pevensie children – Lucy, Peter, Edmund and Susan – are sent away to the countryside by their mother, while their father fights in the war.

Taken in by an eccentric professor, Lucy is the first of the children to discover a magical wardrobe that opens into a snow covered forest. She meets a faun named Mister Tumnus (played with charm and wit by James McAvoy) who delivers Lucy back to the wardrobe before she attracts the attention of the White Witch. She is played brilliantly by Tilda Swinton, who deftly avoids any Cruella Deville comparisons with a seductive, formidable performance.

After Lucy pulls the rest of her siblings into the land of Narnia, they encounter a pair of talking beavers who tell them the White Witch has enslaved the land for a hundred years, but fears a prophecy which says “two sons of Adam and two daughters of Eve” will come to liberate Narnia.

The kids flee the White Witch and her wolves to meet up with a lion named Aslan (voiced by Liam Neeson, replacing Brian Cox), who has gathered an army of centaurs, eagles and every other animal in the Book of Genesis to combat the White Witch. An epic battle ensues with the children leading the way.

Directed by Andrew Adamson – the visual effects supervisor who co-directed Shrek and its sequel – The Lion, The Witch and the Wardrobe is the first in a series of seven Narnia films to be produced by Walden Media – the production company owned by billionaire Philip Anschutz – and released by the Walt Disney Company.

Judging by the rocky start the Star Trek and Harry Potter franchises got off to, there’s reason to hope the Narnia films will improve too, because this one is like two different movies, one great, one flat.

In the first hour, the filmmakers take time to build the relationship between the children, transport us from wartime London to the countryside and explore the mysterious manor belonging to the professor (Jim Broadbent) with childlike wonder. Lucy’s arrival in Narnia and her mutual fear and fascination upon encountering the hoofed Tumnus is perfect.

The casting of the Pevensie children is spot on. Of the four, the compassionate Lucy (Georgie Henley) and the traitorous Edmund (Skandar Keynes) are given far more in the way of a character to play by Lewis’ narrative than the older siblings, but the young actors all are quite good.

Tilda Swinton kicks ass and takes names as the White Witch. I don’t know where she learned fencing, but her physical acting in the climactic battle scene is the most intimidating sword play I’ve ever seen an actress pull off. Every great action film needs a strong villain, and this film definitely had one.

An action sequence involving wolves chasing the children and the talking beavers onto a melting ice flow is exciting, but upon arriving at the battle camp and introducing us to Aslan, the movie stalls. Much of this is probably a fault of Lewis’ narrative – I never read the books as a kid – but are in full view in the movie.

Aslan’s computer generated rendering (courtesy Weta Workshop) and Neeson’s line readings are all right, but I never felt any sense of awe about him. This completely renders what’s probably the story’s biggest scene, his self-sacrifice at the Stone Table, completely ho-hum. Despite being the centerpiece of the marketing campaign, Aslan isn’t even on screen for more than ten minutes.

I also didn’t care for the conceit that the Pevensies would lead all of Narnia on the battlefield in the war of the century. We’re given a brief “training” scene where Susan fires a bow and arrow – missing the bullseye – but it made no logical sense to see Peter and Edmund holding their own in a sword fight against a bad ass like the White Witch.

Fantasy films, whether they’re Superman or Peter Pan have a hurdle of imagination to clear, which is, do I believe this? Yes, it’s talking beavers, but it took all of the opening credits for me to accept a talking barnyard in Babe. This film never really made me believe in faeries or want to clap my hands.

Narnia is ultimately not as captivating as Oz, Middle Earth or even Harry Potter Elementary. What’s going on here, who is who and where we’re going are questions that never captivate the imagination. Where did the White Witch come from? Why did she conquer Narnia? What are all of these creatures and where did they come from? There might have been a fantastic answer to these questions in the books, but as a film, they go unanswered. The result is a flat universe.

Maybe it’s unfair to compare this to previous films, but the only reason we have a film version of Narnia at all is that Harry Potter sold billions of books and The Lord of the Rings sold billions of tickets. Both of those film series have their flaws, but The Chronicles of Narnia isn’t on their level yet.