Secrets of the Dragon Sanctuary (Fablehaven 4) by Brandon Mull ****

This is fourth installment for the Fablehaven series. It is about the characters of the previous books trying to get the key for the vault of an artifact that can partially open a demon prison. The key happens to be in a dragon sanctuary (which are more dangerous than Fablehaven) called Wrymroost. 

I like this book because of the danger, drama, derrin-do, and other things the author added.

I recommend this book for ages 8+.