Onyx begins as the hidden training world of the Spartan-III program and is revealed in 2552 as something far more important: a Forerunner shield world built around a protected interior refuge. This episode examines how the activation of Halo installations awakens systems across Onyx and draws UNSC personnel, Spartans, Covenant forces, and Sentinels into a struggle over access to the shield world. Kurt-051, Chief Mendez, Spartan-IIIs, Halsey, and surviving Spartan-IIs become trapped inside a battle whose strategic importance grows as the Covenant discovers the same Forerunner secrets. Kurt ultimately sacrifices himself to prevent the enemy from following the others into safety. The destruction reveals that Onyx itself is artificial, composed of vast numbers of Sentinels that destroy the remaining Covenant fleet. The battle exposes a program hidden even from many UNSC leaders while simultaneously revealing that the Forerunners had once built an alternative to Halo: places designed to survive the firing of the array.
Audio briefing
LISTEN ON HALO HISTORIAN.
This episode is available through its permanent public podcast page.