The second season of the American television series Person of Interest premiered on September 27, 2012 on CBS and ended on May 9, 2013.

The series was renewed for a second season in March 2012[1] and stars Jim Caviezel, Taraji P. Henson, Kevin Chapman and Michael Emerson.

The series revolves around a mysterious reclusive billionaire computer programmer, Harold Finch, who has developed a computer program for the federal government known as "the Machine" that is capable of collating all sources of information to predict terrorist acts and to identify people planning them.

Finch recruits John Reese, a former Green Beret and CIA agent, now presumed dead – to investigate the people identified by the numbers the Machine has provided, and to act accordingly.

During the second season, Decima Technologies, a powerful and secretive private intelligence firm run by ex-MI6 spy and idealist John Greer, is revealed to be attempting to gain access to the Machine.

Reese and Finch encounter Sameen Shaw, a U.S. Army ISA assassin, on the run after being betrayed by her employers.

The Machine is revealed to have developed sentience and covertly arranged for itself to be moved to an undisclosed location to protect itself from interference.

[26] Showrunner and executive producer Greg Plageman added, "We hate it when we watch a show that has a serialized content, there's a cliffhanger where somebody is placed in jeopardy, and then you come back the next episode and it's like nothing happened.

"[26] The writers said that the first episode, "The Contingency", served as a way to get Reese to act on his own while searching for Finch and it would also answer an important question raised by the series: "Who does the Machine turn to?

"[32] After the first two episodes, Acker stated that she would return to the series eventually at some point in the season, saying "I think he [Finch] misses me too much.

Among many characters that were confirmed to return at the beginning of the season included Jay O. Sanders as Special Counsel, Robert John Burke as Patrick Simmons, Annie Parisse as Kara Stanton and Michael Kelly as Mark Snow.

[38][39] In October 2012, it was reported that Mark Pellegrino would also guest star as "an edgy and charming head of a popular publishing empire."

[43] In January 2013, Sarah Shahi joined the series in a recurring role as Sameen Shaw, "a fearless, sexy and witty operative in a secret paramilitary organization that tracks and eliminates terrorists before they can act."

The tomboyishness that came out of me doing this was kind of amazing, and I hope just people buy the end result, because it felt really good and quite natural to just kick somebody's ass.

The producers teased her character before the finale, naming her Mrs. Penn, "a powerful, intelligent and wry 50something femme who never flinches in the face of danger.

[55] On July 14, 2012, the cast and crew attended the 2012 San Diego Comic-Con to discuss and promote the season and show a sneak peek.

[56] Jonathan Nolan, Michael Emerson, Taraji P. Henson, and Kevin Chapman also attended the 2012 New York Comic Con on October 13, 2012 for a Q&A session as well as interviews.

The site's critical consensus is, "Smartly plotted and consistently thrilling, Person of Interest's second season delivers dazzlingly dramatic episodes that skillfully develop the show's overarching narrative.

"[87] Tim Surette praised the premiere episode as "vintage Person of Interest amplified, showing off its trademark combination of complex intrigue, creative action, and clever innovation in bigger ways than ever before."