My Soul to Keep : Soul Screamers bk.3
(Book)

Kaylee has one addiction: her boyfriend, Nash. A banshee like Kaylee, Nash understands her like no one else. Nothing can come between them. Until something does: Demon Breath, the Netherworld kind that really can kill you. Somehow the super-addictive substance has made its way to the human world. But how? Kaylee and Nash have to cut off the source and protect their friends--one of whom is already hooked.