In the 26th century, humanity wages a desperate war for survival against the Covenant, a fanatical alliance of alien races bent on humanity's extermination. Master Chief John-117, a genetically enhanced Spartan supersoldier, stands as Earth's last hope. Guided by Cortana, a brilliant AI, he discovers the Halo installations—mysterious ring-worlds harboring an ancient and terrible secret. Built by the long-extinct Forerunners, these structures are weapons of apocalyptic power, designed to starve the parasitic Flood of its food source: all sentient life. As civilizations burn and buried mysteries unfold, the Master Chief must confront impossible odds, embracing sacrifice in the ultimate battle for galactic survival.
