The Story - Part 3

In the depths of Delta Halo, the Master Chief and the Arbiter finally meet, but they are bound by the Flood. Seething below the surface of the ring for an untold number of years, the parasite had formed into something called a Gravemind. This horrific composition of flesh was an embodiment of its collective consciousness, carrying with it the ability to communicate and to direct the Flood abroad. It is here where the Arbiter learns the true purpose of the Halo installation.

With their paths now crossed and fates intertwined, the Arbiter and the Master Chief are set out by the Gravemind in different directions but with the same goal: prevent Truth from activating Halo.

On the Covenant homeworld of High Charity, SPARTAN-117 and Cortana soon learn that the Prophets intend to personally return to Earth with a massive fleet and a Forerunner dreadnought capable of wiping out the last remnant of humanity. Leaving Cortana behind as a fail-safe against Delta Halo's potential firing, the Chief pursues Truth into the dreadnought and follows him to Earth.

After forming an uneasy alliance with the humans, the Arbiter assaults the installation's control room, narrowly killing Tartarus just before the ring's firing sequence was complete. The stalled activation process, however, was not without consequence. Upon advisement from 343 Guilty Spark, the Arbiter and the humans soon learn that the remaining six Halo installations are now on stand-by and the only way to activate or terminate this process would be from a mysterious location known as the Ark.