Dead man's hand - James J. Butcher

On the streets of Boston, the world is divided into the ordinary Usuals, and the paranormal Unorthodox. And in the Department of Unorthodox Affairs, the Auditors are the magical elite witches with spells at their command and all the power and prestige that comes with it. Grimshaw Griswald Grimsby is... not one of those witches. After flunking out of the Auditor training program, Grimsby tried to resign himself to life as a mediocre witch. But he can t help hoping he'll somehow, someway, get another chance to prove his skill, unfortunately when that chance comes his way, it comes with high risks.