SPOILER FREE:
Young fans of the Percy Jackson series may find themselves a bit slower to warm up to this one. Not impossible, mind you, and I think all of them will still thoroughly enjoy these books. However, I noticed that my ten-year-old was taking longer to read this one, just as he had with book one, The Red Pyramid.
I think the reason for this is not that the books are less well-written, or the characters less well-drawn. These books are every bit as exciting and character-driven as their predecessors. However, they are a bit more densely-packed with unfamiliar information. Geographically, they range much farther than the Percy Jackson series does. Percy's quests take place in the United States. If my son had a question about a location, he usually didn't have to go farther than asking me in order to get more information. Additionally, the mythology itself was more accessible to him (and me). I can't think of any Disney cartoons off the top of my head that deal with Egyptian gods.
Once he realized during the first book that this was slowing him down, he took to reading it near the computer. We bought this book on Kindle, in order to have immediate access to helpful websites, and, suddenly, this is more like his own quest than just a book. He's learning, and he's loving it.
This book, like the last is told from the points of view of dual protagonists: Carter Kane and Sadie Kane. For kids, this may be a bit daunting, as the switch back and forth involves two distinctly drawn characters with different voices. I like it, because my son, who normally shies away from books with female protagonists, is absolutely willing to read this. Thank you, Rick Riordan, for doing something about the bias in kidlit and helping our next generation to learn how to see things from different points of view.
The book contains just enough exposition to get you through it if you haven't read the first (for example, if your child gets this as a gift, you won't have to run straight out and buy the first book before he or she reads this one; however, your child probably will want to read the first book at some point).
Themes you may want to discuss with your child upon reading:
Empire - the concept of empire plays huge in this series, perhaps even more than it did in the Percy Jackson series. This makes the books both relevant and relatable to current events, if you want to bring them up with your child. There's nothing heavy-handed, though, or preachy or judgmental or especially patriotic, so if you prefer to avoid the topic, you won't be asked any questions you prefer not to answer.
Family - The Percy Jackson series was replete with absentee father issues. The Kane chronicles begin with the loss of a father by two kids who had already lost their mother. To make matters worse, the siblings have been separated for years and they do not resemble each other at all. The books so far have dealt deftly with the kids' discoveries of common ground and likenesses, despite their early separation, and the concepts of love and family are never far beneath the surface.
Chaos versus Order - this is the nature of the struggle, and the book doesn't present the choice as an easy one.
I'm still reading most of what my son reads, and I enjoyed this one as much as he did. I'm looking forward to the next installment, and so is he.