Halo has been around for two decades. The Xbox franchise has ten games’ worth of story to follow, quite a bit of which gets very complicated, very fast. That’s all to say. We hope you appreciate just how much work went into trying to make a Cliffs Notes summary of the entire Halo timeline from beginning to end to get every one right and caught up before Halo timeline hits in 2020. Because it wasn’t easy, and there’s a lot of it.
Regarding that last point, this also means we’re sticking with the games here for our history. But suppose you do want to do some extra credit work. In that case, The Forerunner Saga trilogy of novels is your best bet since it explains the whole cosmic backstory of the Precursor race and the Forerunners (Halo story 4’s) and Halo timeline, including the firing of the halo wiki arrays to kill the Flood. It’s a lot. But for right now, let’s focus on the halo games. So, for starters.
First Contact (Halo timeline Wars)
Halo timeline, Humankind has become a space-faring species, but our expansion puts us on the radar of the Covenant, an alliance of alien species who believe humanity’s very existence is an insult to their gods, the Forerunners.
They thus wage a holy war upon us, starting on the colony of Harvest. Humanity barely ekes out a victory there, but not before the Covenant acquires their next target: a planet called Arcadia. The UNSC warship Spirit of Fire travels to the Earth and finds the Covenant wreaking havoc to search for artifacts related to the Forerunners. What they see instead is the Flood, a parasitic lifeforms that infects all sentient life it touches.
Tonight we dine in Hell (Halo timeline: Reach)
The war rages on another 20 years, and humanity’s luck runs out on Arcadia. The Covenant eventually invade the planet Reach, humanity’s military stronghold, and the Spartan program’s training grounds. Elite, genetically modified soldiers, Spartans are trained from birth to be the best of the best. And the best of the best get the snot kicked out of them.
HARD.The Covenant massacre much of the populace, including many of the Spartans. One particular squad of Spartans, Noble Team, steps in and assists in defense of areas of interest and the planet’s evacuation, but it’s a losing battle, and what’s worse, some vital info is at risk. Dr. Catherine Halsey, the scientist responsible for the Spartan Program, sees the way the wind’s blowing and tasks the remaining soldiers with escorting top secret information held by an artificial intelligence named Cortana (crafted to look like a younger and more naked version of Dr. Halsey, which is a weird flex) to an evacuating ship, the Pillar of Autumn. Noble Team succeeds, inadvertently saving the galaxy in the process, but at the cost of their own lives.
Here’s Johnny (Halo: Combat Evolved)
The Pillar of Autumn was holding two secrets. One’s Cortana, who had the coordinates of a ringed world called a Halo timeline, which the Covenant seem desperate to find. The other is one of the last Spartans, the Master Chief, John-117, being kept in cryogenic sleep until needed. That doesn’t take long. Within minutes of the Pillar of Autumn exiting slipspace, it’s attacked by the Covenant, and Chief wakes up just soon enough to install Cortana in his suit and get into an escape pod.
Upon landing and searching for survivors, he discovers the world is a massive weapon and containment facility made for the sole purpose of eradicating the Flood. When the Covenant accidentally release the Flood, the facility’s AI caretaker, 343 Guilty Spark, guides Chief on how to activate the Halo story using a device called the Index. He almost does, until Cortana finds out starting the Halo timeline won’t kill the Flood but deprive them of their food; specifically, all sentient life. As an alternative, Chief finds the crashed Pillar of Autumn and destroys the ring by setting the ship’s reactor to self-destruct.
The Heretic Anthem (Halo timeline 2)
The Covenant is much less happy about the destruction of the Halo story than humanity, and one of the Elite generals in charge of securing the ring is stripped of his rank and sentenced to die by the Covenant’s religious leaders: the Prophets of Truth and Mercy and the High Prophet of Regret. However, the death sentence is carried out in a roundabout way, as the Prophets instead grant the general the rank of Arbiter, where he will be carrying out SEAL Team Six-type suicide missions on the Prophets’ behalf.
The Arbiter’s first mission is to neutralize a rogue Elite who has been blaspheming that the Prophets have been lying to the Covenant. See, the Covenant believes activating the Halo Series is a means of transcendence to a higher plane. The rogue Elite says differently and has 343 Guilty Spark with him to back him up. The Arbiter refuses to listen and still eliminates the Elite. Everything’s coming up Arbiter after that.
Invaders must Die (Halo games 2)
Meanwhile, before humanity can even properly celebrate the Master Chief’s victory on the first Halo Series ring, the Covenant arrives on, of all places, Earth, led by the High Prophet of Regret. After making a beeline down to Earth’s surface, the Master Chief gives an assist to Earth’s military and forces the Prophet into making a hasty retreat, but not before the Master Chief jumps on a new ship, In Amber Clad.
He’s joined by Miranda Keyes, daughter of the poor, Flood-infected captain of the Pillar of Autumn, and Sgt. Avery Johnson, who’s Aponte from Aliens, except Johnson, lives longer. Together, they follow the Prophet through slip space to his destination: a second Halo installation. The Chief does manage to track the Prophet down and end him while Keynes and Johnson drive to swipe the Halo’s Index. However, Covenant cavalry arrives just in time to bombard the Chief’s location, and sending him to what should have been a salty doom.
Children of the Grave (Halo story 2)
Meanwhile, the Arbiter is sent to retrieve the Index from Chief’s buddies and succeeds. However, upon learning of the Prophet’s death, the Covenant’s Brutes, led by a general named Tartarus, seizes command and betrays the Arbiter. He takes the Index so he can activate the Prophets can activate the Halo. After getting tossed down a chasm, the Arbiter and Master Chief are saved by a tentacled horror called the Gravemind, the Flood’s primary consciousness.
While in his clutches, the Gravemind confirms Halo’s right function to the Arbiter and explains what the Prophets’ plan would do. Duly educated, Chief and the Arbiter are released and manage to stop Tartarus from activating the Halo, but there are more significant problems now. The Flood managed to worm their way onto In Amber Clad, crash the vessel into the Covenant’s capital warship, just in time to add some spice to what’s fast turning into full-on Covenant civil war, kept at bay only by Cortana’s insistence on staying behind to blow the ship if the Flood can’t be contained.
Raiders of the Lost Ark (Halo ODST, Halo Series 3)
Back on Earth, a group of Orbital Drop Shock Troopers guarded an alien intelligence called an Engineer defecting from the Covenant, who informs the humans about why the Covenant goes to Earth. As it turns out, Earth is home to an artifact that will lead the Covenant to the Ark, a sort of master remote control for every Halo installation in the galaxy. While the Prophet of Truth does manage to get his filthy hands on the artifact and make one hell of an exit speech on the way of Earth, the Arbiter, Chief, and the Gravemind manage to chase him to the Ark and end the Prophet once and for all.
Finishing this Fight (Halo plotline 3)
Given its seclusion, our heroes decide to activate the new Halo, hopefully wiping out the Flood once and for all while sparing the galaxy at large. Master Chief heads back to the Covenant mother-ship High Charity to rescue Cortana from what can only be described as the Flood’s collective colon. Chief, the Arbiter, and Sgt. Johnson head to the new Halo and learn from Guilty Spark that the unfinished Halo won’t just wipe out the Flood’s food when it fires, but self-destruct.
When Johnson brushes off the info, Guilty Spark attacks him to protect his ring. Chief manages to destroy Guilty Spark, but Johnson dies, the poor guy. Either way, Chief works to activate the Halo and run like hell back to his ship before detonation. However, the ship is torn in half during the slipspace jump. The half with the Arbiter manages to escape to Earth, thus ushering lasting peace between Covenant and humanity. Chief and Cortana, however, are stranded like Tony Stark in uncharted space. And so, the Chief turns on the distress signal, puts himself in cryosleep, and tells Cortana to wake him if she needs him.
Requiem for a Dream (Halo story 4)
Four years later, Cortana wakes Chief just in time for their (half of a) ship to get pulled into an artificial gravity well and crash land on the planet Requiem, closely followed by a few rogue groups of Covenant that aren’t having any of this peace business. Along with having to deal with the hostile natives, a race of bio-mechanical soldiers called Prometheans; there’s another severe complication: Cortana is experiencing rampancy, a sort of Alzheimer’s for artificial bits of intelligence that sets in when they operate outside their planned obsolescence period. Thankfully, Chief picks up a transmission from a human ship, the UNSC Infinity, which picked up his ship’s distress beacon.
To improve communications and warn off Infinity from falling into the same gravity well, Chief attempts to reach what he believes is a communication jamming satellite. However, it is a prison, with only one inmate: a Forerunner called the Didact. After throwing Chief around like a ragdoll for a hot minute, he declares humanity unworthy of leadership and floats off to find a way to restore the pecking order from when the galaxy was young.
Do the evolution (Halo wiki 4)
Chief’s ride eventually does make it to Requiem, with no help from the Didact. The ship’s captain orders Chief on a mission to find a way to disable the gravity well, even giving Chief a badass mech suit for his troubles. Along the way, though, Chief winds up meeting another, less hostile Forerunner called the Librarian.
When the other Forerunners saw the hideous results, they had the Didact imprisoned. But now he’s back, with even more determination to get the Composer than ever. Charging Master Chief with stopping him, the Librarian gives him a lovely parting gift: accelerated evolution, making him immune to the Composer’s effects.
The Older Woman behind the Helmet in a Massive Explosion (Halo games 4)
Chief destroys the gravity well grounding the Infinity, but the Infinity’s captain doesn’t believe the Librarian’s story. He orders a retreat back to Earth, and also that Chief surrender Cortana due to rampancy. Chief refuses, and with the help of a subordinate, Commander Lasky, he follows the Didact through slipspace. As it turns out, the captain might’ve had a point. The Didact finds the vessel containing the Composer, and right when Chief desperately needed Cortana’s help stopping the Didact from using it, the rampancy kicked in, rendering her useless as an entire ship’s crew gets composed.
I Lived, Glitch (Halo timeline 5: Guardians)
Eight months later, humanity helps the Covenant mop up their rogue factions, with the Master Chief given command of a small squad of surviving SPARTAN-IIs. While on a mission on an abandoned space station, Chief receives a weird transmission directing him to Meridian from Cortana. While they do finish the task, Chief and his Team go AWOL immediately after to find her.
Fireteam Osiris, a team of more advanced SPARTAN-IVs led by Jameson Locke, is tasked with bringing Chief and his crew in from Meridian. Upon reaching the planet, Osiris discovers the human colony there under attack by Prometheans led by the Warden Eternal, claiming to be under Cortana’s orders to activate the Guardians, enormous Forerunner defense platforms. While Locke can beat the Warden, his encounter with Chief is a bust. Chief wins Locke in a straight-up fight, and his Team manages to board the Guardian as it jumps to Cortana’s location.
Doing Science and Still Alive (Halo timeline 5: Guardians)
Chief and his Team wind up on the planet Genesis and find Cortana, who’s very much alive with a bit of a makeover (and some clothes, finally). Somehow cured of rampancy by the Forerunner tech in the Didact’s ship, Cortana is burdened with glorious purpose: assuming the stewardship over the galaxy that the Didact thought humanity unworthy of. With the Guardians at her command, her mandate is the forced disarmament of all warring species, under penalty of complete destruction. Unable to convince Cortana that her plan will kill billions, Cortana places Chief and his Team in stasis until the program is comprehensive.
All the Singularities [put a ring on it] (Halo 5: Guardians)
Having obtained several Guardians, Cortana’s plan becomes clear: aside from the Didact, the Forerunners believed humanity would assume what they termed the Mantle of Responsibility, essentially becoming the superior race in the galaxy. According to Cortana, however, the Forerunners had it wrong: it’s not humanity itself, but those they created.