Person of Interest Wiki
Person of Interest Wiki
Episode Overview   Summary   POI   Cast and Characters   Crew    
← Season 3 Person of InterestSeason 4 (Flashbacks in parentheses) Season 5 →
401Panopticon 409The Devil You Know 417Karma” (Finch)
402Nautilus 410The Cold War” (Greer) 418Skip
403Wingman 411If-Then-Else” (The Machine) 419Search and Destroy
404Brotherhood 412Control-Alt-Delete 420Terra Incognita” (Reese)
405Prophets” (Finch) 413M.I.A. 421Asylum
406Pretenders 414Guilty 422YHWH
407Honor Among Thieves 415Q&A
408Point of Origin 416Blunt
Terra Incognita

4x20 - Terra Incognita.PNG



Air dateApril 14, 2015

Running time44:00

Production code3J5420

Written byMelissa Scrivner-Love
Erik Mountain

Directed byAlrick Riley

Chase Patterson
POI 0420 Chase Patterson.png

Images (19)


There are people who care about you, who could love you. You just gotta let them in.

— Carter, to Reese

[Suggest quote]

"Terra Incognita" is the 20th episode of season 4, and the 88th produced hour of Person of Interest. It originally aired on April 14, 2015.


Reese finds himself on a perilous personal journey when he takes on a homicide case Detective Carter was never able to close.

Origin of the Title

The Latin term terra incognita (lit: unknown land) is a cartographic term referring to unexplored or uncharted territory. As the globe was explored, early maps, labeled in Latin, marked those parts of Earth as yet unmapped as terra incognita. The expression and its English translation are also used as metaphors for a new experience or a journey into the unknown. Shakespeare famously called death "the undiscovered country from whose bourn no traveler returns" (Hamlet).


Main Plot Points

The events in this episode are in Machine point of view.

  • Person of Interest: Chase Patterson, a wealthy young man believed to have killed his parents. The murder is originally investigated by Carter, then lands on Reese's desk as a cold case.

Episode Notes

  • This episode uses a more complex structure of flashbacks, memories and eventually hallucinations than we generally see in an episode, most from Reese's rather than the Machine's or Samaritan's point of view. Reese revisits his relationship with Carter through a series of memories and hallucinations, which return him to one evening early in Season 2 where he and Carter are on a stake-out monitoring a member of HR. The episode begins with Reese remembering their conversation during the stake-out. Later, after he is shot and left to freeze to death, the memories morph into hallucinations as his body temperature and heart rate decline, affecting his thinking. The first indication Reese has begun to hallucinate is when Carter refers to "your police shrink."
  • Also woven through the episode are a series of flashbacks detailing Carter's original investigation of the case with Terney, which parallel Reese's present-day investigation. Because these are not in MPOV, they appear to be Reese trying to imagine what Carter would originally have done based on his knowledge of her investigative style and what he finds in the case file.
  • The cold weather was both Reese's friend and his enemy. The extreme cold brings on a condition known a hypothermia, where the body begins to shut down as the result of prolonged exposure and subsequent loss of body heat. Among the first effects of hypothermia is the slowing of Reese's heart rate and the constriction of his blood vessels, which in turn slows blood flow and reducing bleeding. However, as the body's core temperature lowers, mental confusion sets in, resulting in his hallucinations. In addition, muscle coordination is reduced, respiratory rate slows, and blood pressure drops. In the final stages, amnesia sets in and the body's internal organs begin to fail. Despite this, an individual with hypothermia may survive even if they appear to have died; medical warming procedures increase survivability from hypothermia.
  • Reese was unable to drive away once he'd gotten into the car because, as Carter noted, "Cars don't like cold weather." As weather reaches freezing temperatures, the performance of a car's oil and battery changes, ultimately making it impossible to start the car. Both Reese's and Gil's cars had been sitting in the freezing weather long enough to make it impossible to start them without the help of a block warmer or other equipment designed warm the car's engine before any attempt to start it. On the other hand, Fusco's car would have been kept in a far warmer garage, making it possible for him to start his car and reach Reese.
  • This episode brings back the characters of Joss Carter and Raymond Terney through flashbacks and hallucinations. Carter was a main character and member of the Team in the first two and a half seasons while Terney was a recurring character and HR cop who appeared multiple times until his death in “The Perfect Mark”.
  • While going through Carter's effects, Reese discovers the picture of himself and Jessica Arndt Carter recovered in “Many Happy Returns”.

Production Notes

  • The episode never makes it clear whether the POI lived or died. However, Gil stated the drugs administered to Chase gave him eight hours to live. Reese would have died of hypothermia much faster than Chase, but was found alive, making it reasonable that the writers meant us to understand that the POI survived.

Bloopers and Continuity Errors

  • Reese is clearly shot in the back of his right shoulder, but camera shots showing the front of his body place the wound further down by his midsection.


  • "Happy New Year" - Nat King Cole (over the final scenes between Carter and Reese). The song was selected by Jim Caviezel.


  • The "Catskills" is a mountainous resort area located about 3 hours' drive of north of New York city.
  • "We have all the time in the world". James Bond's famous last words from "On Her Majesty's Secret Service".
  • The baby picture of Carter and her son Taylor, is a real life picture of Taraji P. Henson and her son Marcel.
  • Writers Erik Mountain & Melissa Scrivner-Love received an Edgar Award nomination, for Best Teleplay, for their work on this episode.


  • "You brought home a beast. I have to walk it, and water it, and feed it, lest it consume any more of my books." -- Finch, in Reese's flashback with Carter
  • "I've seen a lot of dead bodies. You know what they all had in common? Not a one of them looked like they saw it coming." -- Carter, in Reese's flashback
  • "Not content with an atlas of Patagonia, he then proceeded to devour a first-edition Gatsby." -- Finch, in Reese's flashback, describing Bear's "appetite" for fine leather-bound books
  • "I haven't seen or heard from the coiffed Columbo since this morning." -- Fusco, to Finch regarding Reese's whereabouts
  • "Time? Hell, we got all the time in the world. Benny's asleep, wee hours before Finch brings us breakfast." -- Reese in hallucination conversing with Carter who warns him that time is running out
  • "No, listen to me, John. Your time is running out. You're dying, John." -- Carter in John's hallucination