Samaritan launches a cyber-attack on the stock exchange, leaving the team with no choice but to embark on a possible suicide mission in a desperate attempt to stop a global economic catastrophe.
Danger closes in when the epic battle to bring the criminal organization HR to justice reaches new heights. And when the Machine suddenly gives out Reese's number, the POI team faces their greatest threat yet.
The team seeks justice for Carter's murder, but Finch realizes that one person may go too far in the battle against HR. Meanwhile, NYPD officer Patrick Simmons' number comes up.
The team takes desperate action in its race to prevent Samaritan from coming online and making them its first targets. Meanwhile, the months-long battle with the anti-surveillance terrorist group Vigilance comes to a shocking conclusion.
Reese and Finch team up with surprising allies in a race to save The Machine from Root and the mysterious international organization, Decima, who have both re-emerged with dangerous agendas.