The Better Part of Darkness by Kelly Gay

Atlanta, the town all the other-worlders want to make their new home.  Gateways to other worlds have been opened, and all sorts of creatures you thought were myth are actually real.  One particular world's moon is dying and they want Atlanta to become their new home.   They make a plan and put it forth into action, but the details don't come clear until later.

But as the otherworlders make themselves at home in Atlanta, they bring with them a deadly drug, Ash.  The drug is killing the humans, and  the cops are having a hard time finding the source.  Charlie Madigan is one hard cop, who also is recently divorced and mother of one.  Her partner, Hank, is an otherworlder and they get along pretty good.  But everyone worries about Charlie.  She died a few months ago, and somehow was brought back.  Now, things are different for her.  She has new powers building inside her and she doesn't know what is going on.

A kick-butt top-notch urban fantasy, Kelly Gay has built an extraordinary world where Supernatural meets Die Hard.  The characters are well-developed and the storyline is solid.  A new author on the rise and one I am definitely looking forward to reading more from.