The wall between the worlds has collapsed. The Invisibles have burst into the human world. McKayla wages a war with otherworldly monsters and with a book of black magic - the “Sinsar Dubh” living in the girl is trying to enslave her. McKayla resists, drawing strength from the passionate embrace of the mysterious Barrons. He dies and returns from oblivion again to protect her. His love, like a powerful shield, protects her from danger. If he disappears, she will not be able to survive the duel with the treacherous Princess of the Unseelie...