2552

Early 2552
The Spartans of Gamma Company receive their orders.

July 17, 2552
The Battle of Sigma Octanus IV begins.

July 18, 2552
The UNSC win a victory at the Battle of Sigma Octanus IV. Commander Keyes, of the, plays a critical role in this success. Keyes is subsequently promoted to Captain by Admiral Stanforth. Unknown to the UNSC, the Covenant place a tracker on the hull of the Iroquois. The importance of Reach to the UNSC is revealed to the Covenant when the Iroquois returns to that world.

August 12, 2552
SPARTAN-117 and Corporal Harland are debriefed by ONI at Camp Hathcock, Reach, on the events on Cote D'Azur during the Battle of Sigma Octanus IV.

August 25, 2552
Dr. Halsey and Cortana choose the, with Keyes as her commander, for a secret mission Halsey is planning.

August 27, 2552
All but three SPARTAN-IIs gather at the FLEETCOM Military Complex on Reach, where they learn of their next mission: to acquire a Covenant vessel, navigate to the Covenant home world, and return with captured Covenant leadership.

August 29, 2552
SPARTAN-117 receives a neural interface upgrade, armor, and is introduced to Cortana.

August 30, 2552

 * Cortana has ONI Colonel James Ackerson illicitly transferred to the front. This is her revenge for his attempts to eliminate both her and SPARTAN-117.
 * The Covenant, despite sustaining heavy losses, win a crushing victory at the Battle of Reach. Many of the remaining SPARTAN-IIs are killed.
 * The escapes the disaster at Reach although, due to Cortana, the jump is not blind as per the Cole Protocol.
 * The surviving SPARTAN-IIs on Reach are separated into two groups. One recovers Vice Admiral Whitcomb and goes into hiding at Camp Independence.  The others are admitted into CASTLE Base by Dr. Halsey and receive parts of the MJOLNIR Mark V upgrade and new weapons.
 * Halsey learns of Colonel Ackerson's mysterious plans that seem to involve "her" Spartans.

September 4, 2552
Lieutenant Wagner returns to Earth and reports on the evident destruction of Reach to Colonel James Ackerson, Admiral Hood, and General Strauss at an ONI facility in Sydney, Australia.

September 7, 2552

 * The Time/Date Record Anomaly of Sept 23, 2552 most likely rejoins the timeline here.
 * Dr. Halsey and members of Red Team discover an enigmatic shard in a Forerunner installation below CASTLE Base. They are besieged by Covenant forces who seek to possess the shard.

September 2552
The remaining Spartans, Admiral Whitcomb, Dr. Halsey, Sgt. Johnson, Lieutenant Haverson, Warrant Officer Polaski, and Corporal Locklear jump to Slipspace on board the Covenant/Human hybrid ship Gettysburg-Ascendant Justice, and discover that the shard seems to have the ability to bend both space and time.

September 12, 2552
The Gettysburg/Ascendant Justice arrives for refit and provisioning in Eridanus system and meets with the rebels under Governor Jiles. Dr. Halsey sedates Spartan 087, Kelly, and absconds with her on Governor Jiles' personal ship, the Beatrice. Before she goes, she gives the alien artifact to Corporal Locklear, with implicit instructions to destroy it.

September 13, 2552
UNSC forces aboard the Gettysburg/Ascendant Justice win a crucial victory at the Battle of the Unyielding Hierophant. SPARTAN-093 and Vice Admiral Whitcomb are killed. The survivors, now aboard the singular, depart for Earth to warn of the impending Covenant invasion.

September 19, 2552

 * The Battle of Installation 04 begins.
 * The arrives at Alpha Halo and is forced to crash land on the ring.  A significant portion of her crew survives to continue the fight on the ground.
 * SPARTAN-117 is awoken from cryosleep and tasked with preventing Cortana's capture by the Covenant. The pair escape the ship and land on the ring via escape pod.
 * Captain Keyes and the others in his escape pod are captured by the Covenant. Only Keyes escapes summary execution, and is taken to the  Truth and Reconciliation.

September 20, 2552

 * SPARTAN-117 leads a marine force to board the Truth and Reconciliation. They recover Keyes and escape aboard a Covenant dropship.  Keyes orders SPARTAN-117 to find the "Silent Cartographer", a map room that will reveal the location of the Control Room.  Keyes leaves to lead an assault on a Covenant weapons cache.
 * Having found the map room and the pertinent information, Cortana directs a Pelican to take them to the area where the ring's Control Room is. Upon reaching the Control Room, Cortana transfers to the Control Room's computer and directs SPARTAN-117 to stop Keyes from accessing the 'weapons cache', really a Forerunner quarantine facility.
 * SPARTAN-117, without Cortana, enters the facility but is unable to locate Keyes. Instead, he discovers the "Flood" and is forced to retreat.  He links up with and takes command of the surviving members of Keyes' team and fight their way to the extraction point.  However, the Spartan is conscripted by "Monitor" of Installation 04 and teleported away before he can be evacuated.

September 21, 2552

 * The Monitor takes SPARTAN-117 to the ring's "Library" to retrieve the "Index", a device needed to activate the ring's primary weapon. Having retrieved the Index, the Monitor teleports the Spartan back to the Control Room where an irate Cortana confiscates the Index and prevents the ring from firing.  SPARTAN-117 and Cortana flee a now-hostile 343 Guilty Spark and Sentinels.
 * To forestall the ring from being activated manually, SPARTAN-117 disables the ring's three Pulse Generator. This is to buy time to destroy the ring by activating the auto-destruct on the Pillar of Autumn.  Only Keyes neural interface can activate the ship's self-destruct, and SPARTAN-117 embarks once more to rescue the captain.
 * Cortana teleports the Spartan to the Flood-overrun Covenant cruiser where Keyes is being held. Alas, the pair arrives too late to save Keyes, who has been merged into a Brain Form.  SPARTAN-117 retrieves the neural interface by punching in the former-captain's head.  Cortana downloads the necessary codes, and the duo returns to the Pillar of Autumn on a captured Banshee.
 * 343 Guilty Spark overrides the auto-destruct codes, forcing SPARTAN-117 to manually destabilize the ship's still-functioning fusion cores. SPARTAN-117 and Cortana then escape the resulting explosion and the fragmentation of the ring aboard a Longsword.
 * The Battle of Installation 04 ends.

September 22, 2552
The Master Chief and Cortana, onboard a Longsword in the debris field of the destroyed Halo, find one remaining Pelican containing Sgt. Johnson, Lieutenant Haverson, Warrant Officer Polaski, Corporal Locklear, and a set of cryotubes containing Linda.

September 23, 2552
The Master Chief, Cortana, Linda, Polaski, Sgt. Johnson, Haverson, and Locklear depart for Reach via Slipspace aboard the Covenant Flagship Ascendant Justice, captured near the Halo debris field. A Time/Date Record Anomaly continues from this point in the narrative, resolved above on Sep 7, 2552.

October 19, 2552
The High-Prophet of Regret prepares his private fleet for an endless search for the other Rings, without authorization from the other two high-prophets The survivors of the Pillar of Autumn land on UNSCDF ODA142 "Cairo”.

October 22, 2552

 * The Mjolnir MK VI arrives at Cairo from Songnam, South Korea, giving Spartan 117 a chance to utilize it after Spartan-062 has given it a field-test.
 * At the same time The Covenant council deems the Fleet Commander of Particular Justice a Heretic, and sentences him to death.
 * On the Cairo the Master Chief and Sergeant Avery Johnson receive various decorations for their actions on the Pillar of Autumn, while Miranda Keyes receives a postmortem award for her father's brave sacrifice on the gameplay level, Keyes (Level).
 * The High Prophet of Regret begins to siege the Planet Earth at this point with a woefully underequipped force, not having expected any humans to be present; they attack without messaging the other High-Prophets.
 * The Master Chief successfully destroys one Carrier of the fleet and repels Cairo Station's boarders, but the first Covenant Assault Carrier had already deployed ground soldiers in New Mombassa, Africa.
 * The chief deactivates a covenant bomb in the Cairo and transports it to the second carrier, it is destroyed.

October 23, 2552

 * Spartan 117 is deployed to New Mombassa and drives out many Covenant patrols out of the city, and destroys a Scarab before he can reach the Assault Carrier containing the Prophet of regret, it makes a jump inside the city.

October 24, 2552

 * In Amber Clad follows the tear in Slipspace that the Assault Carrier makes, getting sucked into the vortex along with half of the City. On High Charity the former Fleet Commander is made the Arbiter by the High Prophets of Truth and Mercy.
 * He goes on his first mission, to find and kill the heretic leader. After killing him, ‘Tartarus’ captures 343 guilty spark.
 * SPARTANs-104, 058, and 043 defend Earth during In Amber Clad's disappearance for two weeks.

October 27, 2552

 * The High Prophet of Regret's Carrier and In Amber Clad reach Delta Halo. The Master Chief is deployed with the 7th Orbital Drop Shock Trooper Battalion,(This begins the Battle of Installation 05)following Regret to a lake-based Forerunner temple. He manages to pursue and kill the Prophet of Regret, but doing so causes the now active fleet above to bombard his location, forcing him into the lake to be dragged down under the water by the Gravemind.
 * The Arbiter is sent on a secret mission to retrieve the ‘index’ As he completes his mission Tarturus throws him down in to the depths of the ring-world, on the order of the Prophets. They mark Civil War!

October 28, 2552
Gravemind reveals itself as the Flood intelligence of Delta Halo. He sends both the Master Chief and the Arbiter on a secret mission. Master Chief is teleported to the Covenant holy city, High Charity in pursuit of the High Prophets of Truth and Mercy, who have in their possession the Index. The Arbiter is teleported near the control room; cutting a path toward it through the Brutes guarding the way. The Drones and jackals ally themselves with the Brutes and Prophets, putting themselves against the Grunts, Elites, and Hunters in their new Civil War. The Master Chief's pursuit of the Prophets comes to no avail; Truth has left with the index. Chief is told by the Prophet of Mercy that the Prophet of Truth intends to go to Earth and finish what they had started. the Master Chief fights his way through wave after wave of flood, looking for the forerunner ships energy-transfer unit. The Spartan gets caught in the transfer field, and is thrown into the ship seconds away from launching. As he is jettisoned the Arbiter finds himself locked in combat with Tarturus, killing him but failing to stop him from activating Halo. Miranda Keyes removes the Index before the ring manages to fire, canceling it's destructive wave but sending a signal out that activates all the remaining installations in the galaxy, as well as all Shield Worlds (such as Onyx). She, Johnson, and the Arbiter call a truce to their rivalry in order to seek out the Ark that 343 Guilty Spark informs them of.

November 3, 2552
A very long day, all of the events on Onyx take place on this day.

SPARTANs-104, 058, and 043 re-take an orbital elevator in Havana, Cuba shortly before being given a mission re-direct by Lord Hood, to aid Catherine Halsey on Onyx. The three SPARTANs steal a Covenant ship, Bloodied Spirit and transfer into Slipspace, arriving at Onyx after a slight detour at Joyous Exultation, answering a distress call to all available Elite-controlled craft in the area.

Cortana sends a Slipspace Message to Lord Hood, informing him that the Master Chief is aboard the Forerunner ship traveling to Earth.

November 4, 2552
Dr. Halsey, SCPO Mendez, and the remaining Spartan IIs and IIIs (minus SPARTAN-117, SPARTAN-062 and Grey Team) begin exploring the Dyson Sphere inside of Onyx.