Three decades ago the humans accidently collided with the Covenant on the far edge of the galaxy after which a war started between them. For most part of the battle the aliens known as the Covenant had the upper hand and then the things got a twist. The Covenant perished in the hands of the heroes from earth. Now there is peace all around and humans can breathe free in a free world with no threat of any alien. UNSC sees everything differently at this situation, there is battle still going own against the Covenant, not in outer space but on places that are not noticed by the human colony.
Threats of civil war also roam in the human world which once again is an issue of concern for the government. After thirty years of war, the humans have lost much and reconstruction of the whole colony might take longer than this. In such scenario if a war starts once again the fate of the human world would not be quite different than the Covenant. Between all of this Karen Traviss i.e the author adds the old veteran once again. Dr. Catherine Halsey is back and most of the people think that she died during the war but it is not true.
Not only the legendary doctor is back but she is also doing everything that is needed to save what she created i.e the Spartan. Voice of Euan Morton once again takes us to Onyx where the Spartans along with Katherine have found yet another secret. New situation is created in the series by this book that will lead the audience to HALO: Mortal Dictata and HALO: The Thursday War in the later stage. Team and the scientist that created them are the same but the enemy changes shape in this book and also there are more space secrets that leak this time.
