The second season of Person of Interest premiered on CBS on September 27, 2012, and concluded on May 9, 2013, following its renewal in March 2012. The show follows billionaire programmer Harold Finch (Michael Emerson) and presumed-dead CIA agent John Reese (Jim Caviezel) as they use "the Machine" to prevent deadly crimes, with this season introducing the secretive agency Decima Technologies and the assassin Sameen Shaw, who eventually joins their team. Key plotlines include Reese rescuing Finch from the villain Root, Detective Carter seeking vengeance for her boyfriend's murder, and the Machine revealing its sentience by secretly relocating itself to an undisclosed location. The season was a major success, averaging 16.07 million viewers and ranking as the 5th most-watched series of the 2012–13 television season, while also earning positive reviews that deemed it an improvement over the first. Showrunner Greg Plageman and writer Jonathan Nolan aimed to keep the show procedural yet evolving, comparing it to The X-Files and promising viewers surprising twists. Due to its strong performance, CBS renewed the series for a third season in March 2013.