Branded a murderer and forced to flee Nabukko with Keir, Eff has only one chance to stop another Obliviation from erasing everything they have fought to remember. With winter closing in and the mountains all but impassable, their desperate search for the core leads them to an unexpected ally from Eff’s past.

As Eff and Keir venture through labyrinthine caves and frozen forests, and encounter dangerous subterranean creatures, every step uncovers another piece of Nabukko's greatest secret. The truth stretches far beyond the colony, reaching back to the arrival of the Piscius. But shutting down the core comes at an unimaginable cost, forcing Eff to confront revelations that could rewrite everything she thought she knew about her past, her future, and the people she trusts most.

With time running out, Eff must find her lost shipand the key to ending the Obliviations forever before the planet claims them—permanently. But some truths refuse to stay buried, and the final secrets waiting for her will change not only Nabukko's fate, but her own.

For fans of The 100, Aurora Rising (The Aurora Cycle), and Across the Universe.