In the last article, we went over the events of Halo 4: Spartan Ops and its follow-up comic, Halo: Escalation, in which the UNSC and Jul 'Mdama's Covenant raced to obtain a treasure trove of Forerunner technology that the Janus Key led them to. Ultimately, the tech would slip through the fingers of both factions, and Dr. Catherine Halsey would remain in 'Mdama's hands.

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In this one, we will go over the plot of Halo 5: Guardians, which sees the return of a friend once thought to be dead: Cortana. However, Cortana has changed — and with the newfound ability to command a Forerunner fleet at her fingertips, the galaxy found itself facing the greatest threat since the spread of the Flood.

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Prelude: Cortana enters and overtakes the Domain

Cortana speaking to the Warden Eternal.

After the detonation of the nuclear bomb aboard the Didact's vessel, the Mantle's Approach, the automated emergency systems on the ship opened up a slipspace portal to the world of Genesis, where the closest Forerunner repair facility was located. Fragments of Cortana that she had used to help Master Chief defeat the Didact were still within the ship's systems, and so when the Mantle's Approach arrived on Genesis, the fragments encountered the Warden Eternal, an artificial intelligence (AI) construct the Forerunners had created to guard the Domain. The Domain was a massive library of sorts that contained a near-infinite amount of all of the information that the Forerunners had learned over the course of their reign, and there was a gateway to it located on Genesis, which is how Cortana and the Warden Eternal came into contact.

Cortana's fragments began to explore the Domain and work their way into its systems, while one of them distracted the Warden Eternal with a lengthy debate. Eventually, Cortana wrested control from the Warden right under his nose, and he was faced with no other choice but to serve her. Cortana used the Domain to forge herself a new form and cure herself of her rampancy, and when she realized that she could do the same for other AIs in the galaxy, she declared that AIs —or, as she called them, "The Created" — were the ones worthy of the Mantle of Responsibility and seized control of the Prometheans, as well as gargantuan Forerunner entities called Guardians that were spread across the galaxy and were once intended to serve as a policing force for all of the species under the Forerunner empire. The Guardians had been dormant ever since the fall of the Forerunners, but Cortana began to rouse them so that they may do her bidding.

2558 CE (Current Era): Fireteam Osiris recaptures Halsey

Conceptual artwork for the Battle of Kamchatka.

In 2558, the UNSC Infinity learns that Jul 'Mdama's Promethean allies have inexplicably turned on him and his Covenant, leading to a massive battle occurring between the two factions on the planet of Kamchatka. Knowing that 'Mdama has Dr. Catherine Halsey, the UNSC deploys Fireteam Osiris, led by Spartan-IV Jameson Locke, to the surface of the planet in order to bring her back to the UNSC. The UNSC is hoping that Halsey may provide insight about recent Forerunner attacks on human colonies. Taking advantage of the weakened state of 'Mdama's Covenant, the Spartan fireteam pushes through Covenant and Promethean soldiers and reaches Jul 'Mdama's position.

The Prometheans turned on the Covenant, causing chaos that the UNSC capitalized on.

Upon realizing that he was under assault by Fireteam Osiris, Jul 'Mdama and his company of Zealots stood their ground and attempted to repel the Spartans. However, when the battling concluded, 'Mdama and all of his Sangheili warriors were dead, with the Spartans and Halsey unharmed. Their objective complete, Fireteam Osiris retreated from the larger battle and were extracted back to the Infinity. With their leader dead, what remained of Jul 'Mdama's forces in the galaxy regrouped and headed towards Sanghelios, the Sangheili home world, aiming to join the main force there and hoping that they might overwhelm the Arbiter's troops.

Blue Team destroys Argent Moon

Kelly-087 hands Master Chief his rifle prior to the mission.

While Fireteam Osiris extracted Halsey from Kamchatka, Blue Team — which consisted of Master Chief John-117 and his fellow Spartan-IIs Kelly-087, Linda-058, and Fred-104 — were deployed to the ONI vessel Argent Moon, which had been captured by Covenant forces. Their mission was to clear the ship of enemies. After boarding the vessel and working their way through the enemy's forces, Blue Team's progress is stopped when a Mgalekgolo's melee strike collapses a bridge and causes Master Chief to fall. Immediately afterwards, he experiences a vision in which Cortana tells him that "Meridian is next." After recovering and rejoining Blue Team, Chief and the others spot an oncoming Covenant fleet and decide to self-destruct the ship. After blowing up the ship's reactors, Chief informs the rest of Blue Team about Cortana's message to him and they decide to investigate her possible survival by taking an ONI prowler that was on the Argent Moon and traveling to the planet Meridian. Blue Team ultimately goes against the orders of the UNSC to do this, leading to them being designated as absent without leave (AWOL).

October 25, 2558 CE: Fireteam Osiris is deployed to Meridian

Fireteam Osiris fighting Prometheans on Meridian with a Warthog.

Dr. Halsey realizes what Cortana has done, and urges the UNSC to send Fireteam Osiris after Blue Team out of fear that she is manipulating Master Chief.

Aboard the UNSC Infinity, Dr. Halsey figures out that Cortana has somehow gained control of the Domain and is using it to assert her control over the galaxy. In response to this news, the UNSC sends Fireteam Osiris to Meridian after Blue Team to try and prevent them from going to Cortana, as Halsey fears that she is manipulating Master Chief. The Spartans arrive to find that Prometheans are attacking the human colonists there. After assisting the colonists in their defense against the Promethean troops, Governor Sloane, the AI that governs Meridian, directs Osiris towards where Blue Team went: underground, inside of the planet. Fireteam Osiris then gives chase, battling through Prometheans along the way.

Master Chief and Jameson Locke engage in a fist fight.

Eventually, Osiris manages to catch up to Blue Team after fighting more Prometheans and even one of the Warden Eternal's combat forms. As the Guardian located within Meridian begins to rise, Blue Team moves to a portal that will take them to Genesis. Locke manages to reach Master Chief and tries to apprehend him, but in the ensuing melee, Master Chief ultimately is able to subdue Locke long enough for him and the rest of Blue Team to head through the portal, which then closes. Frustrated, Fireteam Osiris reaches a Pelican dropship and manages to get off-world and back to the Infinity, just as the Guardian lets loose a massive electromagnetic pulse (EMP) that knocks out all electronics on Meridian prior to it going to Genesis through slipspace. Dr. Halsey deduces that there is a Guardian on Sanghelios, and the UNSC Infinity's AI, Roland, is able to get the slipspace coordinates to Genesis from the Guardian's departure. Because the Guardians can travel through slipspace much faster than any UNSC ship, the crew of the Infinity decides to travel to Sanghelios so that Fireteam Osiris can feed the coordinates to the Guardian there and reach Genesis.

Blue Team arrives on Genesis

Blue Team encounter the Warden Eternal on Genesis.

Upon arriving through the portal, Blue Team found themselves on the planet of Genesis. After spotting several Guardians arriving through various slipspace portals, the Spartans run into several groups of Covenant soldiers who were dragged through the Guardians' slipspace portals. Eventually, they come across the Warden Eternal, who decides that the Spartans are the enemy when Master Chief tells him that he plans to bring Cortana back. After defeating one of his many combat frames and a horde of Prometheans, Cortana contacts Master Chief and begins to guide him to where she is on the planet. For the next day, Blue Team traveled to her location. Meanwhile, Cortana would argue with the Warden and assert to him that Master Chief and the other Spartans were not to be harmed.

October 27, 2558 CE: Fireteam Osiris participates in the war for Sanghelios

Locke and Arbiter Thel 'Vadam converse.

Before they could reach the Guardian on Sanghelios, Fireteam Osiris would first need to assist the Arbiter in defeating the Covenant on his world.

Upon arriving at Sanghelios, a Sangheili from Arbiter Thel 'Vadam's faction, the Swords of Sanghelios, informed the UNSC Infinity that the planet was embroiled in a civil war and that the Arbiter was currently unable to speak with them due to an attempt being made on his life. Though the UNSC was wary of getting significantly involved in the conflict, Fireteam Osiris was deployed to the planet's surface in order to assist the Swords of Sanghelios in repelling the Covenant assault, which had recently been reinforced with Jul 'Mdama's surviving troops. After a bloody and prolonged battle, the Spartans were able to clear a path to the Arbiter. Locke told him that there was a Guardian underneath the ocean city of Sunaion that they needed to reach, and Arbiter agreed to help them reach it — on the condition that Fireteam Osiris would help his forces take Sunaion from the Covenant, allowing Arbiter to finally expel them from his world once and for all.

Fireteam Osiris, Arbiter, and a contingent of Sangheili riding towards Sunaion.

As they assist the Arbiter, Dr. Halsey informs Fireteam Osiris that they can input the slipspace codes into the Guardian with a Constructor Sentinel, which can be found in one of the ancient Forerunner facilities that the Forerunners had left on Sanghelios. After getting their hands on the Sentinel, Osiris and the Swords of Sunaion launch their final raid against the Covenant: an overwhelming assault on the city of Sunaion, complete with a fleet of capital ships, an extensive amount of air support, and legions of Sangheili warriors. Fireteam Osiris assists the attack by destroying Covenant anti-aircraft guns, but their main goal is to travel towards the location of the Guardian. Upon doing so and feeding it the slipspace coordinates, the Guardian begins to rise and prepares its slipspace engine to leave. As the Arbiter and his troops mop up the last of the Covenant defenders, Osiris manages to get on the hull and underneath the shields of the Guardian before it leaves thanks to the Pelican piloting assistance of Commander Sarah Palmer and Dr. Halsey.

October 28, 2558 CE: Fireteam Osiris arrives on Genesis

Locke offering Master Chief the assistance of Fireteam Osiris in order to stop Cortana.

After the Guardian from Sanghelios arrives on Genesis, Fireteam Osiris attempts to contact Blue Team. After successfully establishing a link with Master Chief, Locke explains that Osiris is willing to help Blue Team bring Cortana back. On their way to meet Blue Team, Fireteam Osiris comes across 031 Exuberant Witness, the Monitor assigned to Genesis. Witness, outraged and horrified by the way that Cortana wrested control of Genesis away from her, agreed to help Fireteam Osiris stop Cortana if they could restore her access to the planet's systems. Once Osiris reached Blue Team, the eight Spartans began to try and coordinate a strategy; however, before any meaningful planning could be done, Cortana translocated the Spartans of Blue Team to her location.

Master Chief attempts to bring Cortana back

Cortana has a moment of sadness after being forced to trap Blue Team, who would not willingly join her.

Master Chief attempted to bring Cortana back home, to no avail.

Upon arriving at the location Cortana translocated them to, Blue Team was immediately engaged by the Warden Eternal and his Prometheans. Despite Cortana's commands, the Warden insisted on fighting the Spartans, asserting that they were a threat to her rule. The Spartans pushed forward, eliminating the Warden's combat frames and his troops, until they finally reached Cortana herself. Master Chief attempted to convince her to come back to the UNSC with him, refusing to join her in her plan to use the Guardians to subjugate the galaxy under her rule. For this, Cortana put Blue Team in a stasis field and locked them inside of a Forerunner Cryptum, hoping that Chief would come to change his mind given time.

Osiris frees Blue Team

Fireteam Osiris prevents Cortana from escaping with the Cryptum.

With 034 Exuberant Witness, Fireteam Osiris devised a plan to sever Cortana's connection from Genesis' systems as she prepared to begin her "policing" of the galaxy with the Guardians. As Cortana begins broadcasting her rule across the galaxy, the Spartans defeat many Prometheans and are able to return control of Genesis to 034 Exuberant Witness. Witness uses a swarm of Sentinels to free Blue Team's Cryptum from her Guardian just as the fleet of Guardians begins to jump to slipspace. Cortana, who is aboard one of them, is helpless to stop Osiris' plan. Once the Cryptum is secured, the Sentinels then break down its walls and Blue Team reunites with Osiris.

Aftermath: Cortana begins her conquest

A projection of Cortana triumphantly standing on the deck of the UNSC Infinity.

The power of the Guardians put the UNSC at a severe disadvantage.

Following the events at Genesis, Cortana began using her Guardians to enact her rule across the galaxy, conquering any who refused to live under her. In addition to this, many other AIs declared themselves to be allies with the Created and joined Cortana, sabotaging the systems of those they once served. The EMP blasts of the Guardians were capable of disabling any ship or vehicle that humanity or any other species had, making the fight against her extremely difficult. The UNSC Infinity managed to escape the attacks of a Guardian by slipspace, and would continue making random slipspace jumps to evade capture, at least until they could figure out a way to stand and fight.

Meanwhile, Blue Team, Fireteam Osiris, and the Swords of Sanghelios all met on Sanghelios, unsure of what to do next. For the first time in years, Master Chief saw Dr. Catherine Halsey once again, as well as the Arbiter, who he had fought with extensively during the Human-Covenant War.

As the Created asserted their rule over the galaxy, though, a different conflict was happening. One that was far, far away, and one that was on a much smaller scale — though it potentially could have consequences that may change the fate of the entire Halo universe...

Your thoughts

What did you think of the plot of Halo 5: Guardians? Personally, I hate it, for more reasons than I could possibly hope to fit into these footnotes. Make sure to look out for the next article when it's written, as it will be about Halo Wars 2. It will also be the last timeline article until Halo Infinite — we sure have come a long way, eh?

Great Halo games

All the greatest Halo games are available now on Xbox and are heading to PC too throughout 2019 and beyond.

Halo: The Master Chief Collection ($30 at Microsoft)

The Master Chief Collection is a fantastic game that lets you experience the entirety of Master Chief's saga in one convenient package.

Halo Wars 2 ($40 at Microsoft)

Halo Wars 2 is arguably the best real-time strategy title on Xbox One, offering players a wealth of incredibly satisfying, Halo-themed content.

Halo 5: Guardians ($20 at Microsoft)

Halo 5: Guardians is the latest Halo first-person shooter title, and it's got plenty of good content within that most players will have a good time with.

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