Halo: The Story So Far

Bailey Meyers

With Halo Infinite’s release just around the corner, Spartan fans everywhere may be wondering: wait, there’s a campaign mode? And, while—yes—multiplayer is Halo’s bread and butter, and—double yes—it continues the tradition of being incredibly fun in the newest game, players should also take a minute to check in on good ol’ Master Chief. New to Halo’s single-player adventure? We’ve got you covered. No need to go back and play every game in preparation for Infinite, because this is the story so far:


The first game in the Halo series sets the stage for all the 26th-century sci-fi shenanigans by introducing slip-space, aka faster-than-light travel, which allows humans to colonize alien planets. The planet Reach operates as the main hub for all things “advancing the species”—it’s the main stomping ground for all the big science and military personnel, including the United Nations Space Command (UNSC).

The UNSC are, of course, up to some sci-fi shenanigans of their own. They’re secretly working creating an augmented army of super-soldiers, which they call “Spartans.” Of course, they’ve got their reasons for wanting a mega-powerful military force—a technologically advanced alien race, known as the Covenant, have declared a religious war against the entirety of the human race, since (according to them) humans are basically an affront to their gods. (Citation needed.)

Though the Spartans fight well against the enemy Covenant, there are too few of them to make any kind of a difference, and the Covenant destroys Reach. The Pillar of Autumn, a fancy sci-fi starship, escapes the destruction with everyone’s favorite guy-in-a-suit, Spartan Master Chief Petty Officer John-117, on board. The Pillar of Autumn jumps to slip-space, which is when the actual plot of the game starts kicking in.

When the Pillar of Autumn exits slip-space, it comes upon a large ringworld structure—and also, the Covenant, who followed them as they made their escape. The Covenant attacks and damages the ship, forcing the Autumn’s captain, Jacob Keyes, to give the ship’s artificial intelligence system, Cortana, to Master Chief in a last ditch effort to keep the Covenant from finding Earth. The crew abandons the Autumn, crash-landing on the ringworld below.

After making less-than-graceful contact with the ground, Master Chief and Cortana work to find and rescue the other survivors, only to discover that Keyes has been captured by the Covenant.

Master Chief (and some of the other soldiers, but they don’t matter as much) comes to the rescue, saving him from the Covenant ship Truth and Reconciliation—not exactly a name that rolls off the tongue. In his captivity, Keyes learned that the Covenant called the ringworld “Halo” (hey, that’s the name of the game!) and that they think it’s also a weapon. Of course, that means Master Chief et al. have to find a way to stop them from using it. While Keyes attempts to locate a weapons cache, Master Chief and Cortana strike the ringworld’s control room. Cortana does some of her own cool sci-fi shenanigans, entering Halo’s computer systems, but discovers something major (to be revealed) and sends Master Chief to find Keyes.

During his Keye-quest, Master Chief stumbles upon a brand-new enemy, the Flood—a spooky, parasitic alien species that definitely wants to cause some trouble. Halo’s caretaker, an AI called 343 Guilty Spark, teams up with Master Chief in order to activate Halo’s defenses and protect it against the Flood. Master Chief grabs the ring’s activation index, but Cortana stops him before he can use it—because, apparently, installing it would destroy all sentient life in the galaxy. 343 Guilty Spark, annoyed that its perfect Flood-defeating plan was thwarted, attacks Cortana and Master Chief.

At this point, our heroic duo need to destroy the installation in order to save the day, and, to do that, they need to find Keyes (since he has a neural implant that can destroy the Autumn, which would then destroy Halo with it). There’s just one small problem: Keyes has been assimilated by the Flood. Uh oh! Master Chief retrieves the neural implant from Keyes’ body, then takes it back to the Autumn, where he almost gets exploded (but doesn’t). Not as lucky as our guy MC? Most of the Covenant, the Flood and the UNSC forces, who get wiped out with the Halo installation.

HALO 2 (2004)

After the total fiasco at the end of the first game, the Covenant is looking for a little retribution. Halo 2 begins on the Covenant capital city-ship, High Charity, with a Covenant Elite commander getting stripped of his rank and branded a heretic for his inability to stop Halo’s destruction. (Also, they torture him a little bit, just for funsies.) However, they don’t execute him, and instead give him the chance to become an Arbiter, which he seems pretty happy with! So happy, in fact, that he squashes a rebellion and uncovers our old frenemy, 343 Guilty Spark.

Meanwhile, on Earth: Master Chief and Sergeant Avery Johnson receive commendations for their bravery in the last game. Captain Keyes’ daughter, Commander Miranda Keyes, also accepts a medal (on her dad’s behalf). However, the happy funtimes are cut short when a Covenant fleet appears and starts blowing stuff up. In the turmoil, a ship carrying the Prophet of Regret sneaks past Earth’s defenses and besieges the African city of New Mombasa. However, once Master Chief destroys the invading forces, Regret makes a quick retreat, with Keyes, Master Chief, Johnson, and Cortana in hot pursuit on the UNSC ship In Amber Clad. The team uncovers another Halo installation, so Keyes has Master Chief go kill Regret while she and Johnson dig around for Halo’s activation key, the Index.

Regret sends out a distress call, and High Charity comes to the rescue—but not quite soon enough to save Regret from Master Chief, who then falls in a lake and gets yoinked away by big gross tentacles. The Arbiter arrives, overpowers Johnson and Keyes, and grabs the Index. Tartarus, the impressively named Chieftain of the Covenant Brutes, shows up and shares that the Prophets have ordered that the Elites be destroyed. Then he knocks the Arbiter into a chasm. Honestly, the Arbiter is having kind of a rough week. After he’s done falling, though, he bumps into good ol’ Master Chief, as well as the Gravemind, the hivemind of the Flood. The Gravemind breaks the news to the Arbiter that the Great Journey (aka the crux of the Covenant’s whole dang religion) is a whole dang lie, and sends the Arbiter and Master Chief off to different places to stop Halo’s activation, with the Master Chief heading to High Charity right in the middle of a Covenant civil war. In Amber Clad (at this point fully taken over by the Flood) crashes into the city, and Cortana realizes they’ve made a huge mistake: the Gravemind was only using them as a distraction. The Flood overruns the city, and the Prophet of Mercy is consumed. Master Chief follows the Prophet of Truth on a ship headed out of the city, and Cortana stays behind to destroy High Charity and Halo, should Tartarus succeed in his mission to activate the ring.

An unlikely duo of the Arbiter and Avery Johnson team up to take on Tartarus in Halo’s control room. The Arbiter is unable to persuade Tartarus that the Prophets lied to them, and Tartarus activates the ring. In the resulting battle, Tartarus is killed. Keyes removes the Index, Guilty Spark says some vaguely sinister stuff about an “Ark,” and Truth’s ship arrives on Earth with Master Chief in tow. Everything that happens immediately after this is covered in the comic book series Halo: Uprising, which is very good, but decidedly not a video game, so we’re gonna keep moving.

HALO 3 (2007)

Master Chief arrives on Earth, where he meets up with Johnson and the Arbiter. The trio set off for a UNSC outpost, where they find Keyes and Fleet Admiral Lord Terrence Hood, a commander of the UNSC Home Fleet who also happens to be voiced by Hellboy himself, Ron Perlman. Keyes and Hood are working on a plan to stop the Covenant’s leader, the High Prophet of Truth, from activating an artifact of the ancient Forerunner race. Unfortunately, Truth goes ahead and activates the artifact anyway, so all that planning was for nothing. The artifact creates a slip-space portal, which he (and his followers) hop right through. A Flood-infested ship crashes nearby, and Elite forces arrive to blow everything up, stopping the Flood from spreading further. Cortana had left a message on board for everyone, and, after giving it a listen, they follow Truth through the portal—joined by our old pal Guilty Spark!

On the other side of the portal, the gang winds up on the far edges of the Milky Way, where they discover an enormous structure: the Ark. From the Ark, Truth can remotely activate all the Halos. Then, things go from bad to worse: the Flood shows up on High Charity and begins to infest the installation. Then, things go from worse to worser: Truth captures Johnson (because he needs a human to use the Forerunner tech) and Keyes is killed trying to rescue him. Truth forces Johnson to activate the rings, which prompts Master Chief and the Arbiter to hop back into a truce with the Gravemind so that they can defeat Truth and his army. Shocking no one, the second the Arbiter kills Truth, the Gravemind turns on the seemingly rock-solid partnership.

Master Chief learns that the Ark is building another Halo—a replacement for the old Halo that he blew up. Master Chief activates the Halo, as it would destroy the Flood infestation without destroying the galaxy (hopefully). Master Chief et al. rescue Cortana, who has the Activation Index of the destroyed Halo, but also has some bad news: the Gravemind is trying to rebuild itself on the ring.

When the team goes to the control room to activate the ring, Guilty Spark tells them that, because the ring isn’t finished, activating it would destroy it along with the Ark. Johnson ignores the warning, so Guilty Spark straight-up kills him to protect the ring. Master Chief immediately avenges his comrade by destroying Guilty Spark, but it doesn’t change the fact that Johnson is dead. It’s all very sad! Master Chief activates the ring, escaping the destruction on the UNSC frigate Forward Unto Dawn. Unfortunately, the force of the explosion collapses the slip-space portal, so only the front half of the ship (with the Arbiter on it) manages to make it back to Earth. Everyone is very sad that Master Chief is dead—however, it turns out he’s only sleeping. Yep, Master Chief is in cryonic sleep on the back half of the Forward Unto Dawn as it drifts aimlessly through space, leaving Cortana alone to drop distress beacons and talk to herself.

HALO 3: ODST (2009)

Halo 3: ODST is a side story taking place between Halo 3 and Halo: Reach, featuring new characters in a unique film noir-inspired setting. It’s an interesting game that’s worth checking out if you’re looking for something a little different than the usual Halo vibe, but, since it has nothing to do with our buddy Master Chief, we aren’t going to spend any more time talking about it.

HALO: REACH (2010)

Another non-Master Chief game, Halo: Reach is nonetheless a killer entry to the series—well worth a playthrough for any Halo fan—and acts as a prequel to the main story. Taking place shortly before the events of Halo: Combat Evolved, it follows Noble Team, a UNSC spec-ops unit, who discover that Covenant forces have invaded Reach. After the team fights off the attack, they meet up with Dr. Catherine Halsey, the scientist responsible for the Spartan program and the developer of the Mjolnir powered armor that they all wear. She’s extremely smart but not exactly sorry about kidnapping a bunch of children and turning them into genetically augmented super-soldiers—but, you know, nobody’s perfect.

After the team discovers another invasion force, and assists in defeating them, the surviving team members are entrusted with transporting Cortana to the UNSC Pillar of Autumn, but the mission doesn’t exactly go off without a hitch. As the Noble Team is picked off one by one, the last person standing is the player character, Noble Six, who fights solo against a massive Covenant onslaught, dying tragically in a heroic effort to save humanity from invaders.

HALO 4 (2012)

Four years after the events of Halo 3, the back half of Forward Unto Dawn drifts toward the shield world Requiem, a Forerunner planet. Cortana wakes Master Chief up from the galaxy’s biggest nap just in time for a newly formed Covenant splinter faction to board the half-ship. Forward Unto Dawn (or, what’s left of it) gets caught in the pull of Requiem’s gravity well, resulting in a spectacular crash-landing. Master Chief and Cortana survive and begin to explore Requiem, facing down both Covenant forces and mechanical Promethean Knights.

Unfortunately, in the midst of all of this, Cortana malfunctions, and reveals to Master Chief that she’s been suffering from a condition known as “rampancy,” a decline in mental state that most commonly affects AIs who last longer than their typical seven-year lifespan. Master Chief, confident that Dr. Halsey can fix Cortana, swears he’ll get them both to Earth.

Before they can figure out how to actually, you know, do that, they receive a barely comprehensible transmission from the UNSC Infinity, who picked up their previous distress call. Cortana tries to warn the Infinity away, and instructs Master Chief to deactivate what she thinks are communication jammers. Unfortunately, this results in Master Chief accidentally releasing an ancient Forerunner warrior known as the Didact, and, boy, this guy does not like humans. The Didact seizes control of the Prometheans and the Covenant faction, then launches an attack on the Infinity.

Master Chief successfully gets in contact with the Infinity, and works with them to defend against the Didact’s onslaught of attacks, leaving the Didact vulnerable. Master Chief and Cortana attempt to persuade the Infinity’s captain, Andrew Del Rio, into taking advantage of the opportunity and launching an attack of their own against the Didact. However, Del Rio instead orders them to destroy the gravity well trapping the ship on Requiem. While doing so, Master Chief gets a message from another Forerunner—the Librarian, aka the Didact’s wife and ancient humanity’s protector.

She fills Master Chief in on what happened before his metal butt landed on Requiem: the Forerunners were struggling to protect themselves from the Flood, which (logically) led to the Didact capturing humans and forcibly converting them into Promethean Knights using a device ominously called “the Composer.” Ultimately, the Librarian stopped her mad scientist husband by imprisoning him, which  was working great until some tin dingus accidentally set him free. Whoops. The Librarian, sensing Master Chief needs all the help he can get, gives him immunity to the Composer.

Once the gravity well is destroyed, Del Rio orders everyone to return to Earth, but Master Chief doesn’t want to hand over the malfunctioning Cortana. He defies orders, staying behind to take on the Didact himself (and keeping Cortana by his side). Our ragtag duo trails the Didact as he jets off to another Halo ring, Installation 03. The Composter was moved to a nearby research station, which Master Chief tries to defend from both a Covenant onslaught and the Didact, but the Didact manages to get a hold of it anyway. He uses the Composer on the research station, turning everyone except Master Chief into Prometheans. (Thanks for that immunity, Librarian!)

Master Chief and Cortana follow the Didact to Earth, and board the Didact’s ship with a nuclear warhead. Cortana overwhelms the Didact’s shield by inserting copies of herself into the Didact’s computer system (even though Master Chief told her not to, uh oh!), but the Didact still manages to aim the Composer at Earth.

Before the entire world gets robotified, Master Chief defeats the Didact, who is sent tumbling into a portal below the Composer. Master Chief then activates the warhead, but Cortana sacrifices herself to save him, and it’s weirdly romantic considering she’s a computer program. A rescue team finds Master Chief and takes him back to the Infinity, alive, but sad about his dead robot girlfriend.

Six months later, the Infinity returns to Requiem, still overrun by Prometheans and the Covenant splinter faction, which is now being led by a dude named Jul ‘Mdama. ‘Mdama considers himself to be “the Didact’s Hand”l—also, he keeps sending anonymous messages to Dr. Catherine Halsey, who is aboard the Infinity thanks to her knowledge of Forerunner tech. Spartan Commander Sarah Palmer arrests Halsey for communicating with ‘Mdama, but she uses her technical know-how to force the ship’s AI, Roland, to assist her in striking a deal with her pen pal. Turns out they have a common interest: they both want to find the Librarian. Roland breaks free of Halsey’s control, and guards arrive to arrest her, but not quickly enough. Promethean forces storm the Infinity and capture Halsey, teleporting her to ‘Mdama’s base.

Infinity captain Thomas Lasky receives orders to kill Halsey, but he’s hesitant to follow through with the command, so Commander Palmer takes matters into her own hands and heads down to Requiem to find and kill the rogue scientist. Lasky summons his own soldiers to stop her. Meanwhile, Halsey manages to make contact with the Librarian and receives the two pieces of the Janus Key, a device that can locate all of the Forerunner tech in the entire galaxy, which Halsey can use to advance humankind. Halsey gives one half to ‘Mdama and the other to Lasky’s soldiers, and then Commander Palmer shows up and wounds Halsey in the arm. ‘Mdama and Halsey teleport away again, and ‘Mdama sets Requiem to collide with the nearby sun, because he’s a big fan of a dramatic exit, apparently.


Eight months later, Spartan Fireteam Osiris sets down on the planet Kamchatka, home base of Jul ‘Mdama’s splinter Covenant faction, in an effort to grab Dr. Halsey. The mission is a success, but Halsey warns them that a new threat is imminent. Meanwhile, Master Chief leads his own team (the Blue Team, a very creative name) on a mission to secure the Argent Moon research station. Jul ‘Mdama’s forces arrive and, in the chaos of battle, Master Chief receives a message from his previously-assumed-dead-robot-girlfriend Cortana, instructing him to go to the planet Meridian. Argent Moon is destroyed and, instead of heading back to the Infinity as commanded, Master Chief leads his team to find Cortana. Captain Lasky is forced to declare the team AWOL, and instructs Fireteam Osiris to hunt down and capture their Blue comrades. Blue Team manages to evade Osiris by boarding a Guardian, a massive Forerunner construct, which teleports them to the planet Genesis. There, they are greeted by Cortana herself, who reunites with Master Chief and tells him that her rampancy was cured by Forerunner technology, which also saved her life.

Meanwhile, Osiris finds a Guardian of their own, which they intend to use to track down Blue Team. However, hitching a ride on a Guardian is easier said than done. This particular Guardian is located on the Sangheili homeworld of Sanghelios, which is engulfed in civil war, exacerbated by perennial pain-in-the-butt Jul ‘Mdama. Osiris teams up with the Arbiter (remember him?) to take down ‘Mdama’s forces, after which they grab their Guardian and head off to Genesis. Once they arrive, they meet the planet’s caretaker, an AI named 031 Exuberant Witness, who tells them that Cortana intends to use the Guardians to achieve galactic peace—through force. 031 Exuberant Witness teams up with Osiris; together, they find the Blue Team and break the news.

Master Chief still wants to save Cortana, and tries to talk her down from her plan, but she’s not willing to hear it and locks Blue Team in a Forerunner prison. Osiris wrangles control of Genesis and transfers it to 031 Exuberant Witness, while Cortana escapes via Guardian and begins to amass an army of loyal AI.


Now that you’re all caught up, you’re more than ready to guide Master Chief on his journey to save his robot girlfriend. In Halo: Infinite, he has a new AI in tow, but he’s still determined to find Cortana and make things right. The only question is: can he? Halo: Infinite is releasing on Dec. 8 for Xbox and PC. For more information about the Halo universe, visit halo.fandom.com.

Bailey Meyers
Bailey Meyers is the Gaming Content Producer at FANDOM. She is a Twitch affiliate (@bailienvspredator) and YouTuber (@Goosedrunks).