AOIFE'S KISS by Tyree Campbell

In the urban legends it is said that when Aoife kisses you, she takes you to a better place, a better world. Thus the disappearances of children and the elderly are explained. But now the elderly are turning up dead. And Aoife is to blame.
 
The search for Aoife, be she angel or demon, has reached a dead end. The cold case has been assigned to Inspector Marie Brennan, to work on in her spare time. But when Aoife’s journal turns up, she goes to the one person who might be able to help her find the mysterious woman—an embittered and disabled veteran named Andy, who operates a tavern.

The trail takes them into the world of Kate, an adolescent street girl who rules the alleys like a Romanov . . . and into the world of corporate greed and a sinister and deadly government conspiracy that threatens to murder tens of millions of people.

Only Aoife can stop it. But first, she has to be found.