NEW YORK TIMES BESTSELLER • MacKayla Lane and Jericho Barrons return in the epic conclusion to the pulse-pounding Fever series, where a world thrown into chaos grows more treacherous at every turn.
As Mac, Barrons, Ryodan, and Jada struggle to restore control, enemies become allies, right and wrong cease to exist, and the lines between life and death, lust and love, disappear completely. Black holes loom menacingly over Dublin, threatening to destroy the earth, yet the greatest danger is the one MacKayla Lane has unleashed from within: The Sinsar Dubh—a sentient book of unthinkable evil—has possessed her body and will stop at nothing in its insatiable quest for power. 
The fate of Man and Fae rests on destroying the book and recovering the long-lost Song of Making, the sole magic that can repair the fragile fabric of the earth. But to achieve these aims, sidhe-seers, the Nine, Seelie, and Unseelie must form...