Continues the story of the ancient Forerunners engineering race, who are worshipped as gods by the Covenant while their mysterious connection to humanity slowly unfolds.

After the defeat of the Covenant and the death of billions of people, Dr. Rachel Halsey, thought to be dead, discovers a technology that can save mankind, as the Kilo-Five hunts for her and the Venezia colony makes plans to attack a weakened Earth.

2559. Formerly one of the Covenant's greatest and most fearsome warriors, Arbiter Thel 'Vadam is now allied with his former human enemies while deeply entrenched in leading the Sangheili people to a new era of unification. But his aspirations are under constant threat, whether by the dangerous, warring factions of rival Sangheili keeps, or the relentless shadow of oppression spread by the renegade artificial intelligence Cortana. An opportunity to...

In the first, desperate days of the Human-Covenant War, the UNSC has enacted the Cole Protocol to safeguard Earth and its Inner Colonies from discovery by a merciless alien foe. When the Prophets send their best--an ambitious and ruthless Elite--to destroy the the Outer Colonies and acquire the location of Earth, a three-man renegade squad led by Navy Lieutenant Jacob Keyes fights to hold together a shaky alliance between human survivors and the Covenant...

In the 26th century, Earth's United Nations Space Command and the Covenant, a coalition of aliens, are engaged in a war within the Halo universe for ultimate control, in a collection of four stories depicting various conflicts during the struggle.