A review by kitsuneheart
In Too Deep by Jude Watson

4.0

Woah. The stakes finally got higher. Dan and Amy continue their search for the 39 clues, but another mystery has been presented: were the deaths of their parents the result of an accidental fire...or an intentional one? Amy begins to recall details of that night, straining her relationship with her brother. But the relationship between the siblings and their au pair also begins to be tested, as the Cahill children start to realize that Nellie is a bit better prepared for this adventure than any young woman really should be.

I'm always surprised at the consistent interest I have in this series. It's basically just National Treasure for kids, but it's well-written from author to author, and I do appreciate that they don't hide the real author under a pseudonym (I'm looking at you, Warriors). They're quick and simple, but the plot keeps moving, so even adults are going to wonder what happens next.