December 2553. Less than a year after the end of the Covenant War, a string of violent incidents continues to threaten the tenuous peace in human-held space, culminating in the assassination of UNSC fleet admiral Graselyn Tuwa and the abduction of her family. It is a provocation so outrageous that the Office of Naval Intelligence must retaliate swiftly and ferociouslybut only after its operatives identify her killer and rescue the hostages.
This mission will be the first for homicide-detective-turned-ONI-operative Veta Lopis and her young team of Spartan-IIIs, and something feels wrong from the start. The obvious suspect is an infamous Brute who leads the Keepers of the One Freedom, an ex-Covenant splinter group in fierce opposition to the UNSC. But Lopis and her team soon realize that the truth is much more insidious than they could ever have imagined, and with Fred-104, Kelly-087, and Linda-058 of Blue Team for combat support, they must stop a plan hatched in the bowels of the secret research station Argent Moona plan so sinister it could destroy all those still reeling from thirty years of intergalactic conflict .
- Belligerent Sexual Tension: Both Veta and Fred display a mix of this as well as UST.
- Big Bad: Intrepid Eye is the mastermind behind everything.
- Blackmail: How Intrepid Eye gets her agents to cooperate. It also allows her to turn them into The Scapegoat.
- Butt-Monkey: Castor, despite being the leader of the Keepers of the One Freedom, is constantly being beaten up or misled by others.
- Continuity Nod: The Banished from Halo Wars 2 are mentioned and the Keeper's fear of them is a minor plot point.
- Dirty Coward: Arno Castille proves to be one of these when the Spartans and Veta get the drop on him.
- The Dog Was the Mastermind: Intrepid Eye is a glorified groundskeeper robot and she's running rings around ONI and the UNSC. At the end of the book, no one is aware she's manipulating events.
- The Dreaded: The Spartans are this to the criminal underworld. So much so a plan is derailed due to the fact the criminals are willing to turn over undercover ONI agents to them rather than fight or run.
- Fantastic Racism: Intrepid Eye truly despises humans and wishes they weren't the Reclaimers. However, as they ARE the Reclaimers, she has to figure out ways of making them worthy of the Mantle of Repsonsibility.
- Going Native: Veta has adopted far quicker to ONI's service than she ever expected. They've even provided her a suit of modified Spartan armor.
- Lotus-Eater Machine: A Downplayed Trope example is the Sanctuary of the Keepers. It is a Forerunner location which projects a field of tranquility. This was apparently a place criminals were sent to regain their sense of calm. Intrepid Eye hopes to use it to make humanity a more deserving species.
- The Man Behind the Man: Intrepid Eye is revealed to be spoiler: the power behind Dark Moon and the biological weapon that's the heart of the story.
- Manipulative Bastard: Intrepid Eye plays everyone like a fiddle. Even though she fails this time, she's nowhere near beaten.
- Private Military Contractors: Dark Moon is a private security firm which is powerful enough to challenge ONI and carry out its own paramilitary operations. It was created by Intrepid Eye using her hidden computer connections.
- Revealing Cover-Up: ONI never would have suspected anything if not for the Tuwas being kidnapped.
- Shoot the Dog: Veta discovers some Gao citizens being held prisoner by the Keepers. She is forced to abandon them in order to carry out her mission.
- The Social Darwinist: Intrepid Eye believes humanity needs to be purged of the weak and immoral to make them worthy of the Mantle of Responsibility. She plans to do this using a biological weapon our heroes destroy.
- Team Mom: Even more so than the first book, Veta has adopted this attitude toward the Ferrets.
- Worthy Opponent: Veta Lopis is judged to be this by Intrepid Eye.