- "A replacement, for the ring you destroyed."
- — The Arbiter observing the second Installation 04's construction alongside John-117.
The Replacement for Installation 04 was a partially constructed Halo Ring which was started at the Ark after the destruction of the original Installation 04.
Background
This Installation was designed as a near identical replacement to the previous Installation 04. This was to ensure that the Forerunner's Halo Network was intact, and therefore able to encompass the entire Milky Way galaxy.
History
Creation
Immediately after the Battle of Installation 04 and the destruction of Installation 04, The Ark was notified, and an automated function began building a replacement for the missing Installation's position.
The main weapon was built first with the surrounding circular metal structure after it. It is unclear how the Ark was able to create the new installation or what the source of raw materials for its construction was, as no insight is given to those functions of Installation 00.
Before it was released into space (presumably work was to finish there before being sent to Threshold to replace the original Installation 04 destroyed at the end of Halo: Combat Evolved) the Installation has a number of primary features available even though it was still not complete, these included the environment, atmosphere and main structures and the main weapon, though the ring structure was not yet stable enough to survive this weapon's discharge.
The ring was also not connected to the other Installations, allowing a tactical pulse to be fired without triggering the other 6 Installations. It is never revealed if this is an option available to completed installations as well, although it is likely Installation 04 (II) merely had not been set up with this network yet, as it was incomplete..
Discovery
The new Installation was released into space just above the Ark, but was still incomplete. The Master Chief and the Arbiter decided that the only way to stop the local Flood contamination (which included the Gravemind from Installation 05) was to fire the incomplete Installation, which was out of range of the other Halo rings.
The Chief headed to the Flood-controlled High Charity to retrieve Cortana, as she has the Activation Index from the first Installation 04.
After retrieving Cortana, during his flight from High Charity, the Chief destroyed the main reactor core (at Cortana's suggestion). This greatly damaged, but did not destroy, the Gravemind. Aided in his escape by the Arbiter, the Chief found a crashed Pelican on the exterior of High Charity and piloted it to the Control Room.
The Pelican crashed in a snowy valley near the Control Room, which was situated atop a high tower (as in Installation 04's). As the Chief and Arbiter made their way towards the tower, Flood dispersal pods descended from the sky, and the Gravemind revealed that he was not yet defeated.
After battling to the top of the tower, aided by Sergeant Major Avery Johnson and his Spartan Laser, the team reunited with 343 Guilty Spark.
Destruction
As they entered the Control Room, Spark stated that the Installation would be ready to fire in "just a few more days", and that a premature firing would destroy the ring, and the Ark with it. However due to the gravity of the situation, Johnson replied curtly that they didn't have "a few more days," and attempted to unite Cortana with the Control Core.
This was too much for 343 Guilty Spark, who regarded the installation as his. He entered full Rampancy, (or he could have just been carrying out his original programming, which would have been to ensure the safety of any Installation) and fired on Johnson with his advanced Sentinel Beam, mortally wounding him.
The Chief rushed to Johnson's aid, but was knocked down by Spark's beam, which was then turned on the Arbiter, who was knocked out of the door, which closed. As Chief tried to get up, he was fired upon again, however, his shield took most of the blast. In the ensueing battle, when the Chief was cornered, Johnson fired his Spartan Laser on Spark, before lapsing into unconsciousness; this stunned Spark. Johnson gave the Laser to the Chief with the words "Kick his ass." After three shots from the Laser, Spark exploded and the Chief was finally able to unite Cortana and the Core.
As Spark predicted, the ring was not ready to fire, and it began to shake itself apart and disintegrate. Master Chief attempted to save Johnson but he replied with only "Send me out...with a bang." before closing his eyes. Master Chief and the Arbiter escaped through the first Phase Pulse Generator room, and then to Johnson's Warthog. The vibration of the activation began to tear the Installation apart, causing explosive reactions all across incomplete sections of the installation. Master Chief and the Arbiter barely managed to reach the UNSC Forward Unto Dawn, before the ring detonated. Cortana stated that the ring's explosion "did a number on The Ark."
Trivia
- In the Control Room the hologram of Threshold is missing and if the control room is viewed from above it looks like an entirely black circle. If Threshold was present it would have a blue center, this draws parallel to a glyph during the Iris campaign, which was missing the circle in its center compared to all the others.
- The map Avalanche from the Legendary Map Pack, takes place on Installation 04 (II). Note, the Ark is and the Milky Way are missing from the sky background graphics.
- It may also be possible that this Installation had a Flood Containment Facility, just like Installation 04, although there will probably be no Flood in those facilities, as it was just created.
- Unlike the first game, the first Phase Pulse Generator room is reachable by a narrow ledge(beginning at the top of the control room spire), than only by a fly-able vehicle.
Sources