Showing Blood Trinity by Sherrilyn Kenyon

Atlanta has become the battlefield between humans and demons. All her life, Evalle Kincaid has walked the line between the two. Her origins unknown, she's on a quest to learn more about her past - and her future.

When a demon claims a young woman in a terrifying attack and there's no one else to blame, Evalle comes under suspicion and the only person who might help her is Storm, a sexy new agent with secrets of his own.  Now she's on a deadly quest for her own survival. Through the sordid underground of an alternate Atlanta where nothing is as it seems, to the front lines of the city where her former allies have joined forces to hunt her, Evalle must prove her innocence or pay the ultimate price.

But saving herself is the least of her problems if she doesn't stop the coming apocalypse. The clock is ticking and Atlanta is about to catch fire . . .