The listing, Black Heart by Christina Henry has ended.
PB VGC Bk 6 of Black Wing Series. As a former Agent of Death, Madeline Black is no stranger to witnessing violent ends, but being the one to cause them is an entirely different story... Despite her having saved Chicago from a vampire invasion, the Agency wants to get Maddy off its payroll-----permanently. With the deadly Retrievers hot on her trail, she has no choice but to trust Nathaniel to port her to safety. But the exotic and dangerous world she winds up in doesn't provide her with the peaceful sanctuary she sought. Caught in a turf war between a group of fae and a disturbingly familiar foe, Maddy soon discovers that the twisted plots of her grandfather Lucifer and his brothers extend even into this unknown realm.