Person of Interest is an American science fiction crime drama television series created by Jonathan Nolan that premiered on September 22, 2011, on CBS. It is produced by Nolan, alongside J.J. Abrams, Bryan Burk, and Greg Plageman. It stars Jim Caviezel as John Reese, a former CIA agent who is presumed dead. He is approached by a mysterious billionaire named Harold Finch (Michael Emerson) who is trying to prevent violent crimes before they happen by using an advanced surveillance system dubbed "The Machine", which turns out to have evolved into a sentient AI. Their unique brand of vigilante justice attracts the attention of two NYPD officers, Jocelyn "Joss" Carter (Taraji P. Henson) and Lionel Fusco (Kevin Chapman), whom Reese uses to his advantage as he investigates persons of interest. Reese and Finch are later aided by Samantha "Root" Groves (Amy Acker), a highly intelligent computer hacker and contract killer whom the Machine later identifies as its "analog interface", and Sameen Shaw (Sarah Shahi), a former ISA assassin who unknowingly dealt with the "relevant" numbers found by the Machine. From season 3, the series sees the advent of a new rival AI called "Samaritan", which is brought into existence by Decima Technologies. Much of season 4 is centered on the struggle between the two competing AIs and their human agents.