It's 2535. It is the first, desperate days of the Human-Covenant War, and the United Nations Space Command has enacted “the Cole Protocol” to safeguard Earth and its inner colonies from discovery by its merciless alien foe. Many are called upon to rid the galaxy of lingering navigation data that could potentially reveal the location of Earth and ensure the destruction of humanity. 

One hundred thousand years ago, the galaxy was populated by a great variety of beings. But one species - eons beyond all others in both technology and knowledge - achieved dominance. They ruled in peace but met opposition with quick and brutal effectiveness. They were the Forerunners - the keepers of the Mantle of Responsibility, the next stage of life in the Universe’s Living Time. And then they vanished. This is their story.

In the company of a young girl and an old man, Chakas begins an epic journey across a lost and damaged Halo ringworld in search of a way home, an explanation for the warrior spirits rising up within, and the reason for the Forerunner Librarian’s tampering with human destiny.  

Launch once more into galaxy-spanning conflict and legendary heroism, shards of an ever-expanding journey where human and alien alike find their finest hours in facing their greatest challenges. These scattered stories span untold millennia, from the age of the ancient custodial race known as the Forerunners to the aftermath of the Covenant's bloody war against humanity and even the shocking events surrounding the resurrection of the mysterious Guardians.

It's 2524. Harvest is a peaceful, prosperous farming colony on the very edge of human-controlled space. But humanity has unknowingly trespassed on holy ground - straying into the path of the aggressive, theocratic empire known as the Covenant. What begins as a chance encounter between an alien privateer and a human freighter soon catapults all of mankind into a struggle for its very existence. But humanity is also currently locked in a bitter civil war of its own: the Insurrection. 

The 26th century. Once considered clandestine, the Spartan-II program has now gone public. Tales of armored supersoldiers fending off thousands of Covenant attacks have become the stuff of legend. While the Master Chief defends a besieged Earth and the myriad factions of the Covenant continue their crusade to eliminate humanity, an ultra-secret cell of the Office of Naval Intelligence known as “Section Three” devises a plan to buy the UNSC vital time. It will need hundreds of willing soldiers, though - and one more Spartan - to get the job done. 

One hundred thousand years ago, Chaos rules the final days of the Forerunner empire. The Flood - a horrifying, shape-changing, and unstoppable parasite - has arrived in force, aided by unexpected allies, and internal strife has desperately weakened Forerunner defenses.  

It's 2553. With the 30-year-long Covenant War finally over, the Office of Naval Intelligence faces old grievances rising again to threaten Earth. Angry and bitter colonists - still wanting to settle scores from an insurrection put on hold for three decades - crave justice...as does a man whose life was torn apart by ONI when his young daughter was abducted for the SPARTAN-II program.  

It's 2553. Welcome to humanity’s new war: silent, high-stakes, and unseen. This is a life-or-death mission for the Office of Naval Intelligence’s black-ops team, Kilo-Five, which is tasked with preventing the ruthless Sangheili, once the military leaders of the alien alliance known as the Covenant, from regrouping and threatening humankind again. What began as a routine dirty-tricks operation - keeping the Sangheili occupied with their own insurrection - turns into a desperate bid to extract one member of Kilo-Five from the seething heart of a brutal civil war.  

Molly Patel was only seven years old when the alien alliance known as the Covenant destroyed her homeworld and killed her family. As one of the few to escape the glassing of Paris IV, and despite the United Nations Space Command winning the war on behalf of humanity, Molly never forgot how much she had lost. Nine years later, when her adoptive parents - research scientists specializing in ancient Forerunner technology - are called to the mysterious and wondrous place known as Onyx, Molly vehemently objects.

It is 2555, more than two years after the Master Chief went missing in action following a decisive conflict on Installation 00 - the massive, extragalactic Forerunner construct known as the Ark - as part of the final chapter in humanity's bloody 30-year struggle against the overwhelming forces of the Covenant.

2526. It has been more than a year since humanity first encountered the hostile military alliance of alien races known as the Covenant, and several weeks after the United Nations Space Command’s devastating counterattack of Operation: SILENT STORM was deemed an overwhelming success. The UNSC has put its faith in the hands of the Spartans, led by the legendary Master Chief, John-117: enhanced super-soldiers raised and trained from childhood via a clandestine black ops project to be living weapons.

It's 2552. The theocratic military alliance known as the Covenant is showing no mercy as it continues to assault every human world it encounters, but in the way lies humanity’s greatest champion, the supersoldier Spartan John-117 - the Master Chief. Together with his AI companion Cortana and the last remaining Spartans, the galaxy-spanning fight rages on two fronts following the destruction of the human military stronghold Reach by Covenant forces and the mysterious artificial ringworld known as “Halo” at the hands of the Master Chief. 

It's 2526. It has been almost a year since humanity engaged in its destructive first contact with a theocratic military alliance of alien races known as the Covenant. Now, the hostilities have led to open war, and the United Nations Space Command understands virtually nothing about its new enemy. The UNSC’s only hope lies with the Spartans: enhanced super-soldiers trained from childhood via a clandestine black-ops project to be living weapons. But not everyone wants the Spartans to succeed. 

October 2559. It has been a year since the renegade artificial intelligence Cortana issued a galaxy-wide ultimatum, subjecting many worlds to martial law under the indomitable grip of her Forerunner weapons. Outside her view, the members of Blue Team - John-117, the Master Chief; Fred-104; Kelly-087; and Linda-058 - are assigned from the UNSC Infinity to make a covert insertion onto the ravaged planet Reach.