The writing of this book seems to leave little doubt that Alister McGrath is trying to fashion himself as a modern-day C.S. Lewis. The writing style and target audience of the book sits very much in Narnia territory. The only other modern comparable to it is Philip Pullman's His Dark Materials, though the Aedyn Chronicles does seem to be more simplistic and aimed at a slightly younger audience. More in keeping with the Narnia theme, the story is less an exploration of philosophical and theological thought, and more allegorical. Where it is original is in the subject matter it is allegorising; specifically the Enlightenment period (called, not particularly subtely, The Illumination).
It did come as a slight surprise to me, having read many of McGrath's apologetic works, that here he seems take something of an anti-science view. The heroine of the story, Julia, is clearly speaking McGrath's words and expressing his thoughts, while her older brother, Peter, seems to be a reflection of McGrath's younger self, when he was an atheist (as well as being highly reminiscent of Edmund in The Lion, The Witch and the Wardrobe). One of the great things about this book is that it is full of little nods to other literature and saturated in slightly more subtle references, including Hamlet, Gulliver's Travels and the Exodus of the Israelites from Egypt. That said, the three main 'bad guys' didn't seem to be drawn directly from anything I could think of.
Unlike His Dark Materials, there isn't really enough here to keep the adults interested, but it is certainly a book that I will be handing down to my 7 year old niece.