An attempt to evacuate the planet Sanctuary leads Master Chief and the Spartans to a brutal encounter with the Covenant. With Halsey gone Silver Team finds itself out of favor in the new regime at Fleetcom, and Soren acquires a new asset.
While Halsey attempts to learn about her captor, Master Chief pushes his team to try and get back to the front lines. Kwan learns that the Rubble is a more dangerous place in Soren's absence.
Master Chief's efforts to locate a missing Spartan team gets him in trouble with his superiors, and threatens to fracture Silver Team. Meanwhile Kwan tries to help Soren's family escape from the Rubble as his former crew seizes power.
War comes to Reach, forcing John and the Spartans to fight back against the Covenant amidst the chaos of a surprise attack on a civilian city. Soren and Dr. Halsey have a personal reckoning after they escape confinement.
In the wake of a devastating attack on Reach a wounded Master Chief must regroup with what remains of his allies, while Soren and Laera go in search of their son. Makee attempts to gain information from Cortana.
Talia Perez enters rigorous UNSC training under Kai 125, who is punishing herself for missing the fight on Reach. While in search of Kessler John comes face-to-face with his past, and Makee's loyalties are questioned by the Arbiter's men.
Makee must escape from a coup on board her Covenant ship if she has any hope of reaching the Halo. As Admiral Parangosky throws Spartan lives at a Covenant fleet John and Kai attempt to recover their suits, and Halsey and Miranda have a reckoning amid the ancient ruins on Onyx.
While John and Makee both try to reach the surface of the Halo, Parangosky uses Kai's team and the other Spartans as cannon fodder in a brutal fight with the enemy. Kwan helps Soren search for his family, and Miranda makes a disturbing discovery inside the artifact.
