The war is lost. Humanity has fallen. As the Forerunner's genocidal campaign nears completion, at least one human manages to escape their wrath. Now, 100,000 years later, the last Titan once again finds herself on a journey to save humanity, uncover the past, and reclaim what was lost.

It's up to Stan Smith to save the day.

The Reapers are defeated, but the events to come will make even their atrocities seem insignificant by comparison.

As the UNSC is nearing defeat at the hands of the Covenant, the Allies intervene to prevent the Council from potentially gaining a new ally, and avert the need for another total galactic war.