Battle of Installation 04

Summary
DATE: September 19-22, 2552 (Although it is stated in the level "343 Guilty Spark" that the battle takes place in May).

LOCATION: Installation 04, above planet Threshold Involved: UNSC, Covenant, Flood, and Forerunner construct forces.

Synopsis: The Covenant and Humans both race to uncover the secrets of the mysterious ring, only to discover its horrible purpose. A huge melee ensues between four factions, and eventually the Halo itself is destroyed.

Outcome: The Halo is destroyed. Most Covenant, Humans, and all Flood perish. A handful of human survivors and 343 Guilty Spark escape.

UNSC
Commander: Captain Jacob Keyes

1 UNSC Cruiser: (The UNSC Pillar of Autumn)

1 Spartan II supersoldier: Master Chief "SPARTAN-117"

1 possible Spartan-I soldier: Sergeant AJ Johnson

1 Ship full of UNSC employed Men and Women (including Marines)

The Covenant
Commander: The Supreme Commander of the Fleet of Particular Justice (later promoted to Arbiter)

1 Covenant Fleet (The Fleet of Particular Justice)

The Forerunner Constructs
Commander: 343 Guilty Spark

Hundreds of Sentinels.

The Flood
Commander: None

At least 1 Brain Form

Hundreds of Combat Forms

Thousands of Infection Forms

Timeline
July 17, 2552: The Battle of Sigma Octanus IV. The Covenant recover a Forerunner artifact that contains coordinates to Installation 04. The UNSC recovers the coordinates also, but does not understand them.

August 30, 2552: The Battle of Reach. A single UNSC AI named Cortana, hypothesizes that the data recovered from the artifact are coordinates. She sends her ship, the UNSC Pillar of Autumn into a Slipspace jump towards the installation.

19/9/2552 20/9/2552
 * 0103 Hours: The UNSC Pillar of Autumn exits Slipspace over Installation 04.
 * 0127 Hours: Covenant forces begin attacking and boarding the Pillar of Autumn. Though outnumbered a dozen to one, the vessel manages to destroy at least four Covenant ships and damage some others. One, the Truth and Reconciliation, retreats and descends to Halo's surface to make repairs.
 * The Master Chief is revived by Tech Chief Thom Shephard and Tech Officer Sam Marcus.
 * Sam is soon killed by an Elite and Thom is killed by an explosion caused by the Autumn's space combat with the Covenant.
 * The Covenant attack and force the Pillar of Autumn’s crew to evacuate to the newly-discovered ring world. Lieutenant Hall and Lieutenant Dominique are killed when it crashes.
 * Captain Jacob Keyes is captured by the Covenant and is brought to the CCS-class Battlecruiser the Truth and Reconciliation. Lieutenant Hikowa, Crewman Abiad, Crewman Singh, Crewman Wang, Ensign William Lovell, Corporal Wilkins, Ensign Ellen Dowski, and three unknown Marines are killed when captured.
 * The Master Chief rescues a large number of Marines, taking them on board the Pelican Echo-419.
 * 1038 Hours: SPARTAN-117 and the ODSTs launch an assault on the Truth and Reconciliation. The raid lasts through the night, but the Humans successfully rescue the captain and escape in a captured Covenant Dropship.
 * A pair of Pelicans transport troops, including the Master Chief, to the island where the ‘Silent Cartographer’, a map room that can show the location of Halo's Control Room, is.
 * After saving the new information into Cortana’s data-banks, the two take Echo-419 through a path of underground tunnels the the area where the Control Room is.
 * The Chief finds a group of Marines from Fireteam Zulu that were not "wiped-out" like the rest of the other Marine groups in the area. They lend him their Scorpion Main Battle Tank (MBT).
 * Meanwhile, Captain Keyes, along with Sergeant Major Avery J. Johnson, Corporal Lovik, Sergeant Stacker, Private Wallace A. Jenkins, Private Manuel Mendoza, Private Riley, Private Kappus, and Private Bicenti, acting on information from a disillusioned Elite named 'Qualomee, move towards the Flood Containment Facility under the impression that it is a weapons cache. They are actually moving towards the Flood. In the melee that ensues, Jenkins, Mendoza, Riley, and Kappus are killed and converted to Flood Combat Forms, Keyes is captured, and Lovik and his squad, which includes Stacker and Bicenti, escape.
 * The Chief brings the platoon, along with another he later finds, to a canyon, where Echo-419 is sent to rescue them.
 * The Chief enters the Control room, is warned that the weapons cache that Captain Keyes is looking for is actually a Forerunner base, and that Halo isn’t a Covenant construct.
 * He runs to Echo-419 for a lift.
 * The Chief lands in a swampy area.
 * Whilst exploring around, he discovers the ‘Flood’. He encounters the combat form of Mendoza, tries to reason with it, and is forced to kill it.
 * The Chief finally escapes from the labyrinth of the under-ground research facility via a lift, and he finds Stacker, Bicenti, and the rest of Lovik's team of soldiers.
 * The Chief takes control of the platoon. When Echo-419 is almost at a tower that they chose to meet at, the Chief is captured by the Monitor of Installation 04, who uses the Halo network to teleport himself and the Chief to the Library.

21/9/2552
 * The Chief goes on a search to find the ‘Index’, a Key that can activate Halo’s firing sequence. The Chief reaches the top floor of the Library, after killing at least 200 ‘Flood’. As soon as he grabs hold of the key, 343 Guilty Spark teleports them to the Control Room.
 * When Halo is merely seconds away from firing, Cortana, still inside the computer systems, cancels the firing order. 343 Guilty Spark sends out a message of war to the sentinels.
 * The Chief destroys the 3 Pulse Generators that create the energy used to activate Halo.
 * The Chief is then teleported with Cortana to a Covenant cruiser, where Keyes is being held. The Chief is too late and Keyes has been taken over by the ‘Flood’ and transformed into a 'Brain' form. The Chief takes the neural interface from Keyes, fights his way back through the ship, boards a Banshee and sets a course for the Pillar of Autumn.

22/9/2552
 * The Chief and Cortana crash-land the Banshee into the Pillar of Autumn. The Chief gets inside, and heads to the bridge.
 * 343 Guilty Spark cancels the auto-destruct on the Pillar of Autumn. The Chief is forced to manually destroy the fusion reactors.
 * The Pillar of Autumn is destroyed, along with the ring itself.
 * The Master Chief and Cortana, onboard a Longsword in the debris field of the destroyed Halo, find a Pelican containing Sgt. Johnson, Lieutenant Haverson, Warrant Officer Polaski, Corporal Locklear, and a set of cryotubes containing Spartan 058, Linda.