2560. Humanity finds its back against the wall after the United Nations Space Command flagship Infinity dropped out of slipspace into a devastating ambush launched by the Banished. As this fierce enemy alliance seeks to claim a powerful weapon hidden within the ancient Forerunner ringworld known as Zeta Halo, the surviving UNSC forces now find themselves compromised and its leadership out of reach—with remaining personnel forced to abandon ship and take their chances on the fractured, unpredictable surface of the Halo ring.
Now survival in this strange, alien environment—whether for Spartan super-soldiers or those who never thought they would see the battle up close—is measured day-to-day against a relentless and brutal adversary that always has the upper hand. Desperation grows, but the will to keep on fighting and enduring no matter the odds is never in doubt… even as the Banished seek to unleash a frightening new enemy that could doom them all...