The Rithmatist by Brandon Sanderson

Joel is a student at the Armedius Academy, but his greatest wish is to become a Rithmatist. Rithmatists are able to make chalk drawings on the ground that can be used for defense or to attack others, and they comprise the army that protects the country. Joel knows more about Rithmatists than most of the students at the academy, however he was not chosen to become one at his interning. Then, Rithmatists start to disappear around the country, and Joel's favorite teacher loses his position to a war hero. Parents of Rithmatist students start to panic, and Joel is suspicious of the new teacher. Danger closes in on the academy, and Joel may hold the key to solving the mystery.

Honestly, the whole idea of the Rithmatists' powers was hard for me to grasp in the beginning. I became more comfortable with it as the plot moved along, and the suspense slowly built up to the climax. It really read like a mystery with some unexpected twists. Readers of this book will need to use their imaginations, and I find myself looking forward to the sequel.