The Chronicles of Narnia: The Voyage of the Dawn Treader is the third film adapted from C.S. Lewis' fantasy series. Maybe it's the postproduction 3-D enhancements, but in this effects-laden Odyssey for tweens, sometimes humans and beasts seem more wax-and-paint than flesh-and-blood.

The saga directed by Michael Apted focuses on the younger two Pevensie siblings, Lucy and Edmund (who discover the faraway kingdom of Narnia in The Lion, the Witch and the Wardrobe and help Prince Caspian reclaim the Narnian throne in Prince Caspian). Essentially, they are prisoners of war. As World War II rages and their parents are abroad with their elder siblings, Lucy (spirited Georgie Henley) and Edmund (earnest Skandar Keynes) are confined to their uncle's home in Cambridge, England. Pretty boring for youths who a year earlier liberated Narnia. Even worse, their whimpering cousin can't stop needling them.

Eustace (Will Poulter, of the underknown Son of Rambow), the irritating cousin, takes verbal aim at that make-believe place they natter so much about. Before they can defend themselves from their weaselly relative, the waves in a maritime painting on the wall spill into the playroom and sweep all three of them back into its ocean. Immediately, they are whisked onto the Dawn Treader, a caravel captained by Prince Caspian (the dull if handsome Ben Barnes) and mouse-warrior Reepicheep (voice of Simon Pegg).

The courageous Pevensies and cowardly Eustace think they are helping Prince Caspian in his quasi-Arthurian, quasi-Odyssean quest to reunite lost swords and reawaken missing lords. But as the young heroes do so, each faces an immobilizing personal challenge and finds a means of mastering it. For Lucy, it's vanity and pride; for Edmund, it's envy; for Eustace, it's pretty much all the seven deadly sins. As the youngsters rise to the occasion, they are rooted on by Aslan (voice of Liam Neeson), the Christ-like lion.

Unfortunately, between its ripsnorting beginning and moving finale, Apted's film sails into the doldrums. One need not have familiarity with the source material to understand what's going on (as one requires knowledge of Horcruxes etc. to parse what's happening in Harry Potter and the Deathly Hallows).

But while Apted (versatile director of Coal Miner's Daughter and The World Is Not Enough) gets focused and affecting performances from his young actors, their excellent work gets upstaged by the clutter of computer-generated imagery imperfectly integrated into the overall vision. Apted deftly handles the elements of Christian allegory; it's those infernal digital effects that prove to be beyond his capacity.EndText