Nikki has rescued Jack, and all she wants is to be with him and graduate high school. But Cole tricked Nikki as they journeyed through the labyrinth of the Everneath together, and now she's begun the process of turning into an Everliving herself. Nikki needs to feed on Cole to survive, Cole needs Nikki to gain the throne in the Everneath. Together, Nikki and Jack must travel back to the Underworld to undo Nikki's fate and make her mortal once more.