Forge. Six Degrees, #4

There is a reason Makiah has been volunteering at Lalamore Hospital, the last several months, and it has nothing to do with fluffing up his college application, for the coming year. And Raina, she hits the one craving Makiah wishes he never had; it's a blessing and a curse. Raina and Makiah may not know much about one another, when they first meet, but they do know that neither of them are entirely human. This story has mature subject matter, and concludes Raina and Makiah's story, but there is a continuing story arc into book V.
It should be read in series order.