2559. Formerly one of the Covenant's greatest and most fearsome warriors, Arbiter Thel 'Vadam is now allied with his former human enemies while deeply entrenched in leading the Sangheili people to a new era of unification. But his aspirations are under constant threat, whether by the dangerous, warring factions of rival Sangheili keeps, or the relentless shadow of oppression spread by the renegade artificial intelligence Cortana​​.

An opportunity to break Cortana's chains has suddenly presented itself through the rumored existence of an ancient artifact located on the hostile world of Netherop. Spartan Olympia Vale, trained with the skills to live and thrive among the Sangheili, also recognizes this alien prize as an essential means to aid humanity in reaching the same goal of freedom. But behind the scenes, both 'Vadam and Vale are being manipulated by a mysterious figure with their own agenda. And to make matters worse, all involved are unknowingly placing themselves at perilous odds with forces beyond their comprehension...