Wealthy genius software engineer, who generally goes by the name Harold Finch, is the mastermind behind the creation of an all-seeing machine. Finch and his front man Nathan Ingram devised the machine to sell to the US government, who are unaware of Finch working behind the scenes. The purpose of the machine is so that the government can spot acts leading to terrorism to prevent those terrorist acts from occurring. But what the government considers irrelevant in its use of the machine are acts leading to murder. As such, Finch, without the government's knowledge that he has a back door to the machine, wants to prevent those murders. The machine only provides the social security number of someone involved, Finch unaware if that person is the target or perpetrator. He enlists the help of an ex-CIA special operative who generally goes by the name John Reese to assist in his mission, Reese who is officially listed as dead. But as Reese in particular often uses non-legal means to achieve Finch's end goal, he is tracked by the authorities, who only know him as the man in the suit. They are also tracked by those who are thwarted by the pair in carrying out this mission, and by the few who know of the machine's existence and who have their own nefarious thoughts of what to do with the machine if they can get their hands on it.