This idea of having the power to animate drawings is a great concept, but sometimes you can't help feeling that it could have been slightly better executed. Elements of danger in the plot mean that they use their powers quite often, but hardly any of the animations make you think 'Wow, I wish I could do that'. There are more ideas that wrap into the story; the idea of Hollow Earth, a legendary place where all the terrible things that have ever been imagined are caged, and the Societies that have been built to protect the Animare and the unleashing of Hollow Earth.
Although the twins are in very real danger, most of the book is spent doing what they like and slowly learning new things. While there is a certain degree of danger (in the way that strangers appear and attacks happen), it is not apparent at every moment and the children certainly don't feel that. A very good point is that you never quite know who is in the wrong or not. You feel that all the characters have a point in their beliefs and many do bad things for good reasons, or make the wrong decisions based on their flaws, particularly in the case of the children. In a YA book, that area of grey in morality is very difficult to come by; mostly a character is good or bad, and there is no argument against it. Harry Potter seems like the best example here; Harry is good, Voldemort is bad, Dumbledore is good (no matter how slurred he gets in the press), Bellatrix is bad. You get the drift.
Hollow Earth, as mentioned before, is a book for children and teenagers and so the main characters (Matt, Em and Zach) are all rather young - 12 and 13, to be exact. It is therefore difficult for an adult to empathise with the characters; they sometimes seem a little too lost in their own little world and unthinking when it comes to danger or rules. However, hats off to Carol and John, who have created realistic 12 year-olds who their readers will love.
One idea that was quite interesting to read was when the book went back to the monastery as it was when it was besieged. The way this small story and the main adventure melded together was rather nice, and it added more history to a very contemporary tale. All in all a good little read that kids will love.
However, there is one little thing. It is a trend that is sadly growing stronger as authors try to engage more readers to buy their books and gain a sturdy readership; the story doesn't end. There are still so many questions left unanswered that you just know there will be another book. It leaves us undeniably hanging. yes, there is an excellent and quite surprising climax, which is very well written, but when it then doesn't complete the story with the climax, you finish feeling a little bit scammed.
Still, this book is exciting, magical and a really great concept. It is a great book to read for a child who immerses themselves in magical fiction. 7 out of 10.