In the year 2552, as people on the planet Madrigal battle for freedom from Earth, a deadly confrontation with the Alien Covenant makes matters more difficult.
As John takes Kwan to an Insurrectionist base, where they reunite with Soren, he finds out more about the mysterious object that the Covenant and Makee want to steal.
John uncovers secrets in his memory after meeting his new partner, and Kwan wishes to carry on her people's struggle for independence.
In his quest to search for answers from his past, John takes Halsey and Cortana to where it all started while being guided by his visions.
Kwan and Soren disagree, and John makes a shocking discovery.
Those who survived the battle with the Covenant come back to Reach. John faces Dr. Halsey and her lies.
In order to unearth her family's "true purpose", Kwan embarks on a journey into the deserts of Madrigal, and Soren wants to keep the promise he made to John.
John and Makee reconcile their shared goal, and Halsey has one final opportunity to save her mission and herself.
John 117 leads the Spartans on a dangerous mission to locate the Halo and save mankind.