It is the year 2552.

Humanity has been long at war with the terrifying alien civilisation that collectively calls itself the Covenant.This monstrous conglomerate of warlike species sees humanity as a form of heresy against their religion - a faith based in the single- minded belief that a Great Journey awaits its faithful.

\Unfortunately for this galaxy, must begin with the firing of a series of ring-like weapons scattered throughout space. These vast, terraformed rings are called Halos, and have been long-abandoned by their mysterious ancient creators, the Forerunners.

With time running out, all hopes for the galaxy now lie in the hands of one soldier, Spartan 117 - the Master Chief.