Raid on Installation 08

The Raid on Installation 08 was a small yet crucially significant engagement between the UNSC-Sangheili alliance, the Flood and later the Forerunner Sentinels acting under 343 Guilty Spark's orders. It took place immediately after the raid on High Charity and marked the end of both the Battle of Installation 00 and the Human-Covenant War as an era.

Battle of Installation 00
After realizing that the Prophet of Truth had gained access to the Ark, a joint UNSC-Sangheili attack force was sent through the Portal at Voi to combat the Prophet of Truth's Covenant force there, and stop the Covenant from activating the Halo Array and destroying all sentient life in the galaxy.

The combined forces of the UNSC-Sangheili alliance was enough to completely destroy Truth's forces and prevent the Halo Array from firing. However, the arrival of the Flood hive on High Charity changed the course of the battle. John-117 set out for High Charity. His goal was to retrieve a copy of Installation 04's index from the captured AI Cortana and fire off the newly rebuilt Halo, completely destroying the Flood in and around the Ark.

Raid on High Charity
John-117 landed in High Charity and combated Flood forces deep into their hive. After fighting through waves of Flood forms, he retrieved Cortana, and therefore, the activation index she acquired during the events of the original Battle of Installation 04. The SPARTAN then set High Charity's secondary reactors to explode. He met up with Thel 'Vadam, who had also ventured into the hive to help him, and they took off in a Pelican to activate Installation 08 and destroy the Flood. As they left, High Charity exploded, killing nearly all of the Flood there. Meanwhile, the human and Sangheili survivors from Installation 00 were evacuated to the assault carrier Shadow of Intent which headed back to Earth through the portal.

Battle
John-117 crash-landed the damaged Pelican near the Installation's control room. At the same time, Sergeant Major Avery Johnson landed the on the Installation, far away from the control room. On foot, John, along with Cortana and Thel 'Vadam, made their way to the control room. The Gravemind, having survived High Charity's explosion, sent waves of Flood dispersal pods to prevent the activation of the Installation. The SPARTAN and the Arbiter fought through the Flood forces as they progressed to the top of the tower, with some assistance from the Sentinels and Sergeant Johnson. Once at the top, the team met up with the sergeant, secured the area and entered the control room.

Once inside, the team hesitantly tried to activate the Installation immediately. 343 Guilty Spark, after realizing that firing the partially-completed installation would destroy the ring as well as the Ark, turned against the team. His initial attack mortally wounded the sergeant and blasted the former Arbiter out of the control room. John-117 was severely injured by the initial blast to the point of draining his shield. The SPARTAN was locked into a battle with the rampant Monitor and struggled to destroy it. The mortally wounded Sergeant Johnson took the rogue Monitor by surprise with his Spartan Laser, temporarily incapacitated the Forerunner construct. John, seizing the moment, used the sergeant's Spartan Laser to destroy Guilty Spark. John tended to the grievously wounded Johnson, whose dying words were "send me out, with a bang." Cortana gave her condolences to John, briefly mourning the death of his friend, before firing the Installation using the Activation Index.

As the remaining members of the team exited the control room, they found themselves fighting against both Sentinels and the Flood. During the battle, the team were addressed telepathically by the Gravemind, who warned them that their efforts would only delay the Flood's ultimate goal of consuming the galaxy. The team made their way out of the vicinity of the tower and commandeered an abandoned Warthog left behind by Sergeant Johnson. With the vehicle, the team rode to the Forward Unto Dawn as fast as they could, passing through a labyrinth of construction tunnels, and collapsing platforms. The team eventually made it to the Dawn by crash-landing into the ship's cargo bay. Thel quickly climbed to the bridge and started piloting the ship to safety, while John struggled to hold on in the cargo bay of the vessel. As they approached the Portal, the incomplete Installation fired, causing it to explode and severely damage the Ark. Master Chief John-117, Cortana, and Arbiter Thel 'Vadam had escaped.

Aftermath
This battle apparently marked the end of the Flood threat. As the incomplete Halo fired, it obliterated itself, along with presumably all Flood and Sentinel forces, as well as any surviving Covenant forces on it or the Ark, which being directly below the installation, was severely damaged.

While Forward Unto Dawn was entering the Portal the field collapsed, severing the ship in two. The bow, with Thel inside, made it to the exit coordinates above Earth and crashed into the Indian Ocean. The stern section was less fortunate, being thrown out of the collapsing slipspace field on the way. John and Cortana were trapped in the wreckage as it drifted in space for several years, eventually being caught in the gravity of Requiem, a Forerunner shield world, in 2557. This led to a series of series of skirmishes as the Master Chief and Cortana struggled to find a way back to human space, opposed by a reformed Covenant faction which had sought out Requiem and the Ur-Didact's Promethean forces within the shield world.

Some time after the battle, the UNSC dispatched the scouting vessel to investigate the Ark, following a failed attempt to deploy automated probes to the installation. At the Ark, the Rubicon deployed a number of remote contact teams to the Ark, which had been severely damaged by the incomplete ring's firing. Having detected an anomalous signal, one of the UNSC teams discovered the remains of Guilty Spark's tiny debris among the wreckage and brought him back to the ship. It turned out that Spark was still intact, though his physical housing was irreversibly damaged. However, he managed to upload his consciousness into the ship's computers, purge its AI, render the crew unconscious, and set off on a quest to find the Librarian. With the help of the crew of the Ace of Spades and now residing in an armiger body, Spark met with a personality imprint of the Librarian beneath Mount Kilimanjaro who helped Spark move on from his past and to a new future with the crew of the Ace of Spades. However, Spark was hunted by ONI for the wealth of information he could provide them with.

In mid 2559, the Banished and the crew of the fought for control over the Ark, which by then had fully repaired itself and finished constructing a second replacement ring. At some point during the conflict, the Banished inadvertently released a number of surviving Flood forms from the remains of High Charity, thus starting a second Flood outbreak on the Ark, and validating the Gravemind's final warning. However, after Banished forces killed a proto-Gravemind on the verge of becoming a Gravemind, the Flood were contained again by the Banished and the Ark's Sentinel defense network.

Following the destruction of Installation 08, the Ark constructed a new replacement for Installation 04. By the time the Spirit of Fire arrived at the Ark in 2559, it was nearly completed. The new Halo ring was subsequently launched to the Soell system in an effort to send a distress beacon back to human space, but was intercepted en route by a Created Guardian.

List of appearances

 * Halo 3
 * Halo Legends
 * Origins
 * Halo: Hunters in the Dark
 * Halo Mythos