Batman : Detective Comics Vol. 3 : Gotham Nocturne

"Something is terribly wrong with Batman. No matter the tests Bruce takes, nor the numbers he counts, the greatest detective in the world can't pin down the source of this creeping dread-of his own inner demons and a looming mortality. Meanwhile, real demons roam the shadows as an ancient melody haunts the Gotham night. Here now the curtains rise and as the eerie tune streams in...who is human, who is demon, who is to tell? As Batman investigates the songs and the demons of Gotham, he is forced to confront the oldest question...whether there has been a demon within him all along...and if so, what does it want...and why hasn't it taken over yet?"--