There is an unfortunate tendency for some of these family-oriented movie series to be exclusively written for those who have pored over the inert fantastical babble of the source material or preceding films. (I'm thinking of the second and third Pirates of the Caribbean films as the primary examples.) How obligated is an entry in a series, like The Dawn Treader, the third Narnia film, to re-introduce itself to entry-level audience members? Let's say it is obligated to not put anyone off. The Dawn Treader is for those who follow the series, but also sensibly produced for those new to it, as well (a quick scan of the Narnia Wiki page doesn't hurt, though).