Cold Days The Dresden Files Series, Book 14.

After a brief interlude in the afterlife, Harry Dresden's new job makes him wonder if death was really all that bad in this novel in the #1 New York Times bestselling series. Harry Dresden is no longer Chicago's only professional wizard. Now, he's Winter Knight to Mab, the Queen of Air and Darkness. Her word is his command. And her first command is the seemingly impossible: kill an immortal. Worse still, there is a growing threat to an unfath...