Darkness is growing within Lavinia and if she can't learn to control it, more than just her humanity will be lost. After receiving a cryptic message from the Sea Witch, Lavinia and Jameson must find the Obsidian Caves if they want a chance at stopping Prime. As more hunters arrive at their compound, they learn he's closer to victory than previously believed. Answers won't come easy for any of them, but an infuriating vampire will be the key to bringing everyone together, if only they can trust each other before it all falls apart. The prospect of triumph slips further away as the days pass, but unexpected allies come forward in the form of obvious enemies. Lavinia and crew will need to decide if the rewards outweigh the risks, or if they'll be doomed no matter what they choose.