Season synopsis
Contains spoilers for this season and earlier seasons.
Finch and his allies rebuild the Machine on improvised computers, dealing with errors while Samaritan tightens its control. Shaw remains a prisoner subjected to thousands of simulated escapes and betrayals intended to reveal the team’s location. When she really gets out, she cannot easily trust that her surroundings are real. The reunited group keeps trying to save people, but Finch’s refusal to remove the Machine’s restraints becomes harder to defend as Samaritan attacks them. Root is fatally shot while helping Finch escape, and the Machine adopts her voice. Finch then chooses a drastic counterattack: the ICE-9 virus, capable of destroying Samaritan and the Machine along with much of the infrastructure supporting them.
The final operation follows Samaritan’s attempts to preserve copies of itself, first in Federal Reserve servers and then on a satellite. Finch intends to upload the Machine’s own copy for a final confrontation, knowing a missile will destroy the building used for transmission. Reese and the Machine deceive him about the rooftop, allowing Reese to complete the upload while Finch escapes. Reese dies holding off the attackers, and the Machine’s satellite copy defeats Samaritan. Shaw and Fusco survive their own fight; Shaw later kills Root’s murderer, and Finch reunites with Grace. The surviving Machine downloads back into the subway computers and contacts Shaw through a payphone. Root and Reese are gone, but the work of identifying and helping people continues.