The Flood

Humanity's last hope rests with the crew of the Pillar of Autumn, including the legendary Master Chief, as they flee a devastating alien war. Their desperate jump through space leads them to a colossal, ancient ring world, a mysterious artifact worshipped by their enemies. Crash-landing on its surface, they discover this 'Halo' is far more than it seems: it's a weapon designed for universal destruction, now reawakened.