"Dreamhouse Kings Book 3: Gatekeepers" by Robert Liparulo

Well, I am halfway through the series, and it has (so far) been getting better and better. In fact, there were more overt Christian references in book 3 than either of the other two. The villains have gotten creepier. The house has gotten a little more active. And the King family is getting some unexpected help.
This book marks the first time the family makes progress. I won't tell you what it is, that would be cheating! They are starting to figure out a lot more about the doors and the house in general.
Xander and Dad reconcile a bit more in this book. The kids have made quite a habit out of lying to their dad, using the justification that he had been lying to them about the house. Let's hope the young readers don't miss the point: it is NEVER right to lie.
These books are the perfect length for young readers. Any longer and you run the risk of losing interest. Any shorter, and you would wonder why he had to take 6 books to tell the story instead of just making a trilogy out of it.
So far, I've had no luck in finding books #4  and #5 at my bargain bookstore. I can get it for full price at Lifeway Christian (and I might wind up doing that), but I was hoping to find it for a little cheaper. Not because the books aren't worth the price, but because I'm broke!
Still 5 out of 5 stars!