With Finch missing – kidnapped by his hacker nemesis, Root, Reese enlists Detectives Carter and Fusco to get his friend back, Meanwhile, The Machine never sleeps, disseminating a new number to Reese.

The Machine delivers the number of a cold case that leads Reese ever closer to catching up with Finch and his kidnapper, Root.

With Finch back in the Library, Reese returns to field work, only to face his toughest case yet – protecting the privileged daughter of a Brazilian diplomat.

When The Machine gives them the number of a mob enforcer whose life becomes endangered, Reese and Finch must decide whether to intervene or allow karma to balance the scales of justice. Meanwhile, Finch seeks aid from an unlikely source.

Reese must protect an investigative journalist through surreptitious means to avoid becoming part of her story.

Reese goes undercover in an idyllic neighborhood when The Machine’s latest number sends him to the suburbs.

The Machine gives Finch and Reese the number of a brilliant surgeon, but they soon discover that a resourceful third party has raised the stakes for this POI, forcing them to turn to an unlikely source for help.

The team is spread thin when a husband and wife’s numbers both come up

When the machine names a New York cabdriver as a person of interest, any of his passengers could be a part of the impending crime.

As the FBI pursues "the man in the suit," Reese is even more determined to protect the latest person of interest after learning she is the sister of a soldier who was killed in action.

Finch goes under cover to protect a youth who reminds him of himself; Carter goes on a dangerous mission for the FBI.

Carter tries to help Reese by engaging in mental warfare with the FBI; Reese has encounters with old and new enemies; Detective Fusco must protect supermodel Karolina Kurkova, the latest person of interest.

Reese is abducted by a former acquaintance planning a massive and potentially deadly act of cyber-warfare.

Finch and Reese meet their match: a tech billionaire whose curiosity and endless resources could expose their identities and ruin their efforts to save his life.

As Reese and Finch try to save a hotel maid's life, they encounter a litany of suspects; Detective Carter considers a significant offer from the FBI.

A lethal government operative who tracks and stops terrorist threats before they occur finds herself on the run – and the new focus of Reese and Finch's attention. However, their pursuit proves to be their most formidable when they discover that her remarkable skill set equals their own.

As Finch and Reese try to protect six people simultaneously, clues lead them to a coastal town; when a storm forces Finch and Reese to seek shelter in a police station with a group of locals, they realize a killer may be in their midst.

Kad Stroj izbaci broj direktorice vrhunske tehnološke tvrtke, Finch se infiltrira u njezinu korporaciju kako bi prikupio podatke, ali ne može dokučiti radi li ona u najboljem interesu svoje tvrtke ili je planira uništiti iznutra. U međuvremenu, Carterica nastavlja preispitivati integritet detektiva Beechera nakon što ovaj otkrije inkriminirajuće informacije o kolegi detektivu.

Nakon što netko otruje prominentnu osobu u svijetu medicine, Reese i Finch imaju samo 24 sata kako bi utvrdili koji mu je smrtonosni toksin dan i otkriju tko stoji iza napada. U međuvremenu, detektiva Fusca sustigne korumpirana prošlost kada doušnik Unutarnjoj kontroli dostavi ključnu informaciju zbog koje bi ga mogli strpati u zatvor.

Reese i Finch otkrivaju da je Stroj zbog virusa počeo nepravilno izbacivati brojeve. U utrci s vremenom ekipa traži tehnološkog milijunaša kojeg nitko nikad nije vidio. A zbog svojih nastojanja da ubojicu Cala Beechera dovede pred lice pravde detektivka Carter nađe se na meti zločinačke organizacije Odjel za ubojstva i pljačke.

U zadnjoj epizodi druge sezone Reese i Finch udružuju se s neočekivanim saveznicima kako bi spasili Stroj od poznate im osobe. Otkrivamo i pravu prirodu Fincheva odnosa s bivšim partnerom Nathanom Ingramom. U međuvremenu, Carter Beecherova ubojicu pokušava dovesti pred lice pravde i pritom se nađe u sukobu s zločinačkom organizacijom HR.