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. 

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. 

The 26th century. Humanity has expanded beyond Earth’s system to hundreds of planets that colonists now call home. But the United Earth Government and the United Nations Space Command is struggling to control this vast empire. After exhausting all strategies to keep seething colonial insurrections from exploding into a full-blown interplanetary civil war, the UNSC has one last hope.    

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. 

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.