The Dragon Heir by Cinda Williams Chima

The Weir world is a dangerous place after the wizard uprising in the last book. Jason steals the Dragonstone, the source of all magical power, and brings it back to Trinity, Ohio. Something about Madison has changed since the climax in the last book, and Seph becomes seriously ill whenever he's close to her. Her ability to absorb wizards' powers makes her a potential weapon for the Roses, so there are suspicions that she's acting as a spy for them. Seph survives several attacks from assassins, including a hex coming from one of Madison's paintings, so a magical barrier is built around the town. The safety of Trinity is fading, and the town is becoming a potential battleground for wizards.

You need to read the other books in the series before reading this one. The main characters in this book were minor characters in them. This style is cool, since readers are familiar with most of the characters even though the focus changes. The author adds old problems from Madison's hometown, and it's a little surprising when wizards appear down there too. Bullies are involved, and mortal problems and magical problems overlap. Hints are dropped throughout the plot that Madison's character has hidden powers even though the wizards believe she does not. One thing I liked less in this book is how the plot jumped around to several settings. It caused me to adjust my thinking at the start of each chapter, although I still enjoyed the overall book.