A detective story can be a good way to give an audience insights into a society that is vastly different from the one they are currently living in. This society can be real or fictional, so the detective can be doing detective work anywhere and anytime from the Brezhnev-era Soviet Union to a victorious Nazi Germany in the 1960s. The detective can either be from the location being depicted, or the detective can be a Strange Cop in a Strange Land who learns about the setting along with the audience.
A good reason for making a detective the character who lets the audience explore this kind of setting is that while the detective is often exposed to the failings and dysfunctional aspects of this society, the detective is not from this stratum and can often access locations and information that an ordinary citizen cannot. The detective's work also often takes him or her across class rankings and the various groupings within the social strata; from the prostitutes, drug-pushers and thugs of the underworld to the glittering echelons of high society where the white-collar criminals might hide, from the corridors of power where their superiors in government and politics might be operating to the streets where the lower-level functionaries have to work, and more besides.
In order to qualify for this trope, the setting must be significantly different from the initial intended audience. Works that were set in the present day when they were written and/or set in a location that would have been familiar to the original intended audience, but which have today become snapshots of a bygone era or those which have been exported to locations other than where they were originally made (such as Sherlock Holmes or High&Low) do not count as this trope; however, a work written in the present day but set in the Victorian Era or a work taking place in Japan but written for an American audience would count as this trope.
Historical Detective Fiction is a related trope, but a Tour Guide Detective story could just as well take place in the present day, in the future, or even in an alternate history setting or on another planet. May result in Minor Crime Reveals Major Plot.
- Alien Nation takes place in a 20 Minutes into the Future Los Angeles in which a large number of aliens have landed and formed their own neighborhood. The main protagonists are two LAPD detectives, one human and the other the first alien police officer promoted to detective rank.
- Black Rain is an American film featuring an NYPD detective whose work takes him to Osaka, where he's a Strange Cop in a Strange Land.
- Bright follows a human cop and an orc cop in an alternate, fantastical Los Angeles.
- The Third Man has an American writer investigating the circumstances of his friend's death in postwar, Four-Power-Occupied Vienna.
- Yesterday (not to be confused with the 2004 South African film of the same name), a South Korean film made in 2002, takes place in a reunified Korea in 2020.
- The Spanish film Frozen Silence has a former detective investigating a series of murders among the Spanish volunteer "Blue Division" on the Eastern Front.
- Soylent Green is about a detective investigating a high-profile assassination in a world dying from pollution and overpopulation, and in the process getting to see exactly why the planet is dying and what crimes humanity is willing to commit to keep going.
- American Fuji's main plot has American tourist Alex Thorn forced to learn about Japan and the Japanese people as he tries to figure out how his son, an exchange student, died. Expat Gaby Staunton serves as his reluctant guide.
- The Arkady Renko series by American writer Martin Cruz Smith explore a wide variety of different locations at different points in history, including:
- Gorky Park takes place in Moscow and New York in the late 1970s.
- Polar Star, the next book in the series, takes place on a trawler in the Soviet Pacific fishing fleet during the Perestroika era of the 1980s.
- Red Square takes place in Moscow, Munich, and Berlin in 1991, after the Berlin Wall came down and as the Soviet Union is collapsing.
- Havana Bay is set in Cuba in the 1990s, after the collapse of the Soviet Union resulted in Cuba's "Special Period".
- Wolves Eat Dogs takes place in Moscow and the Chernobyl Exclusion Zone during the Putin era.
- Stalin's Ghost, Three Stations, Tatyana, and The Siberian Dilemma take place in Russia during the Putin era, in Moscow, Tver, Kaliningrad, and Siberia.
- Child 44 and its sequels are much like the Arkady Renko series, except they taking place in the Stalin-era Soviet Union, 1960s New York, and Afganistan during the Soviet occupation.
- Fatherland follows a Nazi Protagonist detective in a world in which Nazi Germany won WWII, dominating Europe from Britain and the Iberian Peninsula in the west to the Urals in the east.
- In the Star Wars expanded universe, Corran Horn served as a detective in the Corellian Security Forces (Corsec); in the X-Wing Series, he often mentions incidents from his time in Corsec which are similar to situations he encounters in the present.
- The First Rule of Survival provides a snapshot of policing in post-Apartheid South Africa.
- The Stainless Steel Rat follows a criminal-turned-crimefighter in a Space Opera setting.
- The Alienist and its sequels follow a criminal profiler in guilded age/turn of the century era New York City.
- Dan Brown's intention for his Robert Langdon novels start out as these; in the books the protagonist is initially trying to solve a crime like murder or kidnapping before uncovering some kind of Ancient Conspiracy, usually filled with religious symbolism. So far the cities explored have been: Rome in Angels and Demons, Paris and London in The Da Vinci Code, Washington, D.C. in The Lost Symbol, and Florence, Venice, and İstanbul in Inferno. Origin was probably supposed to do the same for Barcelona, but ends up being more about Brown's own ideas about evolution of life than about the city.
- Rising Sun is part murder mystery, part Author Tract warning about Japan Takes Over the World.
- Umberto Eco's The Name of the Rose, a serial murder mystery set in a medieval Italian abbey, which explores the Middle Ages' famous fear, ignorance and self-punishment polices.
- In The Yiddish Policemen's Union, a murder investigation explores an alternate-history Alaska in which 4 of the 6 million Jews that would have been killed in the Holocaust were "temporarily" re-settled in Alaska, and Israel was destroyed 6 months after its creation.
- Len Deighton's SS-GB follows a police inspector on a murder inquiry in occupied London in a world where the Nazis successfully invaded Britain in 1940.
- Roger Mac Bride Allen's Isaac Asimov's Caliban: One of the two viewpoint characters is the head of the city police on a Spacer planet, investigating what appears to be an attack by a robot on a human (which ought not to be possible in a world of Three Laws-Compliant robots). The other viewpoint character is the robot who's the prime suspect.
- Foyle's War is set in wartime Britain, and deals with the effects that the war has had on crime and police work.
- Life on Mars (2006) and Ashes to Ashes (2008) start out in contemporary Britain before sending the protagonist of each series back in time to the seventies and the eighties; The American remake does the same thing in New York City in the seventies.
- Mindhunter explores aspects of the FBI in The '70s, from the changes being made in the Bureau in the post-J. Edgar Hoover era to the changing nature of both crime and crime fighting.
- L.A. Noire has the player serve as a police officer and detective in 1947 Los Angeles.
- The Last Express has the player investigate the death of his friend on the Orient Express' last run in 1914 before the start of WWI.
- The Fairytale Detective in the Dark Parables series is a woman from our own modern era who enters fairy tale settings to resolve the issues there. The settings of the fairy tales range from medieval to steampunk, and they somehow exist adjacent to our own real world but most people never see them.
- The titular protagonists of Professor Layton vs. Phoenix Wright: Ace Attorney wind up in the fantastic realm of Labyrinthia, solving puzzles and murders in which magic plays a common role. The game takes advantage of this premise to explore what a medieval society marked by a literal Witch Hunt would look like.