Go back in time, fifty years before the events of New York Times bestselling author P.C. Cast's Partholon books...

Something isn't right at Guardian Castle, and Aine can't figure out what. As Healer, she's supposed to be making things better, but there's a darkness that can't be brightened. And then Aine finds an injured Fomorian--winged, dark, blood-thirsty and inherently evil. Or is he? Because there's something about Tegan that Aine can't resist...and once they've shared blood, Aine realizes that everything she's always believed is going to be cast aside....