Diadem #10: Book of Doom, by John Peel
Hopefully this won't be the last Diadem book, as Peel while Peel answers some questions, he also asks a bunch of new ones. I was a little sad when I finished this book, because I know that my questions won't be answered for a while. Peel's website promises the next two in the series will be published together, hopefully in 2010.
When Oracle and Shanara betray Score, Helaine, and Pixel, the two are trying to prevent the trio from turning into the Three Who Rule. Score is sent to a world of killer plants. Helaine is trapped on Calomir, a prisoner of the Overmind computer. Pixel is a captive in his own mind, with his body possessed by his evil self, Nantor. Jenna shows her worth when she does all she can to rescue her new friends.
The strengths of each character shine, and I was flying through the pages to see what happened next. The history on Shanara shocked me, and while I saw some of it coming, I definitely didn't see all the twists Peel had up his sleeve.
5/5.