The Halo franchise, developed by Bungie and later 343 Industries, spans centuries of interstellar conflict, artificial intelligence, and the legacy of ancient alien civilizations. While the games were released in a nonlinear order, the story unfolds across a tightly woven timeline that begins with humanity's first contact with the Covenant and stretches through the Forerunner saga, the Human-Covenant War, and the post-war rise of new threats.
This timeline presents all mainline Halo games and notable spin-offs in chronological order, aligning events based on in-universe year and narrative continuity, from the fall of Reach to the AI-driven revolution that follows the events of Halo 5.
๐ฎ Halo Wars
In-Universe Year: 2531
Narrative Context
Set two decades before the events of the main trilogy, this real-time strategy game follows the crew of the UNSC Spirit of Fire. Led by Captain Cutter and Professor Anders, their forces engage the Covenant on the planets Harvest and Arcadia. They soon uncover a much larger mystery involving a Forerunner Shield World, Etran Harborage, which houses a fleet of powerful, dormant Forerunner warships. The story culminates in the heroic sacrifice of Sergeant John Forge, who destroys the Shield World to prevent the fleet from falling into Covenant hands. The Spirit of Fire, unable to make a slipspace jump home, is left adrift in unknown space, its crew entering cryosleep for a journey that would last 28 years.
Released: 2009
๐ฎ Halo: Reach
In-Universe Year: 2552
Narrative Context
Showcasing the tragic and heroic defense of humanity's greatest military stronghold, this game has a distinctly bleak tone. Players control Spartan-III "Noble Six," the newest member of the elite Noble Team. The team fights a desperate, losing battle against a massive and unrelenting Covenant invasion force. Key missions include investigating a communications blackout, destroying a Covenant supercarrier, and the dramatic defense of New Alexandria. The game's climax sees the team sacrifice themselves one by one to deliver a fragment of the AI Cortana to the UNSC Pillar of Autumn, setting the stage for the first game. Noble Six's final stand against impossible odds remains a defining moment of Spartan lore.
Released: 2010
๐ฎ Halo: Combat Evolved
In-Universe Year: 2552
Narrative Context
Immediately following the Fall of Reach, the Pillar of Autumn escapes to a mysterious ringworld, Installation 04. Here, Master Chief and Cortana must rally scattered UNSC survivors against the pursuing Covenant forces. Their exploration of the ring soon reveals its true, horrifying purpose when they accidentally unleash the parasitic Flood from a containment facility. They are introduced to the ring's eccentric AI monitor, 343 Guilty Spark, who initially seems helpful but is revealed to be dangerously single-minded. To stop the galaxy-consuming Flood, Master Chief defies the monitor and chooses to destroy Halo by detonating the Pillar of Autumn's fusion reactors in a spectacular, desperate gambit.
Released: 2001
๐ฎ Halo 2
In-Universe Year: 2552
Narrative Context
The story splits into two parallel narratives. On one side, Master Chief defends Earth from a surprise Covenant attack led by the Prophet of Regret, a pursuit that takes him to a new ring, Installation 05. On the other side, a shamed Elite commander is branded with the title of Arbiter and sent on suicidal missions by the deceitful High Prophets. The Arbiter's journey leads him to question his faith as he discovers the lie behind the Covenant's "Great Journey." These paths converge with the outbreak of the Great Schism, a brutal civil war between the Elites and Brutes, and the introduction of the Flood's central intelligence, the Gravemind. The game famously ends on a massive cliffhanger, with Chief vowing to "finish this fight."
Released: 2004
๐ฎ Halo 3: ODST
In-Universe Year: 2552
Narrative Context
Set during and immediately after the Covenant invasion of Earth in Halo 2, this game offers a different perspective on the war. Players control "the Rookie," a silent member of an Orbital Drop Shock Trooper squad scattered during a drop into the occupied city of New Mombasa. With a noir, detective-style atmosphere, the Rookie wanders the city at night, piecing together the fate of his squadmates (Buck, Dare, Dutch, Mickey, and Romeo) through flashbacks. The central plot revolves around uncovering why the Covenant is so interested in the city: they are searching for a dormant Engineer AI that holds vital data about a Forerunner portal to the Ark.
Released: 2009
๐ฎ Halo 3
In-Universe Year: 2552
Narrative Context
Serving as the epic conclusion to the original trilogy, this game sees the uneasy but vital alliance between humanity and the Elites. The fight moves from Earth through a slipspace portal to the incredible Forerunner installation known as the Ark, located outside the Milky Way galaxy. Here, Master Chief and the Arbiter must stop the final Prophet of Truth from activating all the Halo rings. The re-emergence of the Flood and the Gravemind complicates the battle, forcing another desperate plan: activating a newly constructed replacement for Installation 04 to wipe out the Flood locally. The game ends with the Human-Covenant War concluded, but the ship carrying Chief and Cortana, the Forward Unto Dawn, is split in two, leaving the hero adrift and missing in action.
Released: 2007
๐ฎ Halo: Spartan Assault
In-Universe Year: Between 2552–2557
Narrative Context
This top-down shooter bridges the narrative gap between Halo 3 and Halo 4, establishing the new post-war status quo. The story follows early missions of the Spartan-IV program aboard the state-of-the-art UNSC Infinity. Players control Spartans Sarah Palmer and Edward Davis as they battle a rogue Covenant faction that refused to accept the armistice. The plot revolves around thwarting a plan by this faction to weaponize a Forerunner artifact on the planet Draetheus V. While a smaller-scale conflict, it provides important world-building for the UNSC's new role as galactic peacekeepers and the creation of the next generation of Spartans.
Released: 2013
๐ฎ Halo 4
In-Universe Year: 2557
Narrative Context
Beginning the Reclaimer Saga, Master Chief is awakened from cryosleep after four years adrift. He and Cortana discover the Forerunner shield world of Requiem, where they accidentally release the Ur-Didact, a powerful living Forerunner with a deep-seated hatred for humanity. The game introduces the Prometheans, a new class of formidable Forerunner AI enemies. A powerful emotional core drives the story, as Cortana begins to deteriorate from "rampancy," the AI equivalent of insanity caused by exceeding her operational lifespan. Guided by a remnant of the Librarian's consciousness, Chief must stop the Didact from using a weapon called the Composer to digitize and destroy all of humanity.
Released: 2012
๐ฎ Halo: Spartan Strike
In-Universe Year: 2557 (simulated)
Narrative Context
Similar to its predecessor, this game is framed as a training simulation for Spartan-IV recruits aboard the UNSC Infinity. The missions are canonical historical events drawn from ONI records. The simulation revisits the battle of New Mombasa from Halo 2, providing new context, and then jumps forward to a conflict on Installation 03. Here, UNSC forces battle a new Covenant sect attempting to activate a Forerunner artifact known as the Conduit, which has the power to teleport anything in the galaxy. The story is light but adds small, connective pieces of lore to the universe.
Released: 2015
๐ฎ Halo 5: Guardians
In-Universe Year: 2558
Narrative Context
This entry features a dual-protagonist storyline. One follows Master Chief and his original Spartan-II comrades of Blue Team as they go AWOL to investigate mysterious visions from a seemingly alive Cortana. The other follows Spartan Jameson Locke and Fireteam Osiris, tasked by the UNSC to hunt down and retrieve the Chief. The chase across the galaxy reveals a shocking truth: Cortana survived Halo 4 by entering the Forerunner Domain. Believing she alone can bring peace, she has embraced the Mantle of Responsibility and begun a galactic takeover by awakening ancient Forerunner weapons called Guardians, causing AIs across the system to join her "Created" empire.
Released: 2015
๐ฎ Halo Wars 2
In-Universe Year: 2559
Narrative Context
After 28 years of cryosleep, the UNSC Spirit of Fire and its crew awaken to find themselves at the Forerunner Ark, the massive foundry from Halo 3. They are no longer in the Milky Way and are completely cut off from the UNSC. They soon encounter a powerful and ruthless new enemy: the Banished. Led by the brilliant and brutal Jiralhanae warlord Atriox, the Banished are a mercenary faction that successfully rebelled against the Covenant years prior. The story follows Captain Cutter's desperate struggle to survive and establish a foothold against this overwhelming new threat, setting up the Banished as a major galactic power leading into Halo Infinite.
Released: 2017
๐ฎ Halo Infinite
In-Universe Year: 2560
Narrative Context
Following a catastrophic defeat for the UNSC at Zeta Halo (Installation 07), Master Chief is found adrift in space by a lone pilot. He returns to the shattered ring to mount a one-man guerrilla war against the victorious Banished, led by the fearsome War Chief Escharum. His new partner is "The Weapon," a specialized AI created as a copy of Cortana, designed to trap and delete her predecessor. The narrative is deeply personal, focusing on Chief grappling with his failure to save Cortana, his own purpose as a soldier, and his growing bond with his new AI. He simultaneously uncovers Zeta Halo's darkest secrets, including the existence of the imprisoned Endless and their leader, the Harbinger.
