A Covenant assault threatens humanity’s most important stronghold. John, Perez and Silver Team fight an overwhelming enemy. Adm. Keyes rallies the UNSC forces to make a final stand. Halsey and Soren forge an unlikely connection as they attempt to escape captivity.

John and Silver Team embark on an unsanctioned mission. Laera, Kwan and Kessler must escape Soren's mutinous crew. Ackerson receives troubling intelligence from Cortana. The threat of an attack forces Ackerson to make an irrevocable decision.

John pushes Silver Team to its limit as he searches for missing Spartans; Kai worries about John's stability. Kwan finds the Rubble is a far more dangerous place in Soren's absence. Halsey seeks the identity of her captor.

A deadly evacuation mission signals a shift in Master Chief's war with the Covenant. On Reach, a new regime takes the reins at FLEETCOM. John senses a looming threat close to home.