Frozen in Time

When the concept behind a series is so tightly bound to a particular period of history that the series cannot leave that era, it is Frozen In Time. This can be a sliding scale; some series can slip a lot (The Dark Knight is just a Batman story--not "Batman in the 21st Century"), some can only slip a little bit (Sherlock Holmes started in Victorian times and got updated to World War II, but is usually considered Victorian), and some can't slip at all.

This can happen within a single series, or within a long-lasting franchise. It's more common in series that are already set in a historical period (since they're probably set there because the history is important to the story), but it can be more striking when it happens in a series that is initially set in the present day, then remains in that same "present", possibly due to Schedule Slip. If it happens in a single series, there can be strange effects such as having more annual Christmas shows than there were actual Christmases in the defined period. The natural aging of performers can also cause cognitive dissonance when one thinks about how old they are supposed to be at any given point in the series.

Note that this trope is about the setting not advancing. If the setting advances but the characters don't age, that's Comic Book Time.

See also: Not Allowed to Grow Up and Retro Universe. Sometimes caused by Briefer Than They Think. Not to be confused with Time Stands Still.

Anime and Manga

 * In Cyborg 009, Albert Heinrich/004's Backstory involves his attempt to cross the Berlin Wall. In order to keep this in continuity in the 2001 series, the writers had the first four cyborgs created in the 1960s, then put into Suspended Animation for 40 years, at which point the project was continued and the rest of the team 'recruited'. Notable mainly since this was one of the few time sensitive plot points they went out of their way to keep.
 * The anime 009-1 takes place in an alternative universe where the Cold War never ended--because the source manga was so tied to the Cold War that the background had to be kept.

Comic Books

 * A number of superhero characters have origins and backstories tied to World War II in some fashion, though their "current" adventures are usually subject to Comic Book Time:
 * In X Men, Magneto's backstory is irrevocably wedded to the Holocaust. Hence, he keeps getting older (albeit with periodic de-aging due to Applied Phlebotinum or similar plot devices) as his flashbacks feature him younger.
 * The original Justice Society of America (and related Golden Age DC characters).
 * Captain America's case is a bit more complicated than most. Intimately tied in with WWII, the character actually lasted a little into the 50's, fighting commies. When he was brought back in the 60's, it was decided Cap had been frozen towards the end of the war, and all appearances since then had been a fake. The freezing has been convenient for writers since then, since they can just expand the number of years he was frozen as needed to have him unfrozen in the modern era: around 20 years originally, more than half a century for the Ultimate Universe.
 * Nick Fury and the Howling Commandos all fought in World War II. The "Infinity Formula" has been used to explain Nick Fury's continued youth and vitality, but there's no such explanation for the other Howlers, most of whom have also been shown in the "modern" era.
 * Marvel's original The Invaders. There are explanations for why the characters have survived to the modern time, but the series itself remains tied to World War II.
 * Iron Man is an interesting aversion. His origin story takes place in Vietnam (thus tying it to the conflict there), but later versions have retconned the setting, first to an unnamed country in Southeast Asia, and more recently to Afghanistan.
 * Disney. Scrooge McDuck will forever remain a Gilded Age character with roots in the Klondike.

Fan Works

 * The author of With Strings Attached has said that she would have much preferred to set the story in more recent times (it takes place in 1980). However, it being about The Beatles, a certain unpleasant event meant that she was stuck leaving it in 1980, which she doesn't remember too well, being 15 at the time. She gets around this by setting nearly all the story on different worlds and using reference sources to verify any pop culture or technological references the four might make.

Film

 * Walden Media has tied the Earth sections of the Narnia film-verse to World War II. The book The Lion, the Witch, and the Wardrobe is set around the time of the bombing raids, but there it's just an excuse to place the characters where they need to be; the movie added Twenty Minutes With The Luftwaffe to establish it, and it continues to be relevant throughout the film. While later books slip into Comic Book Time, the next two films take deliberate trouble to stay grounded in the period.
 * The original Universal Frankenstein film seemed to take place in the present day, but The Bride of Frankenstein made more of an effort to take place in the 1800s.
 * Austin Powers is basically James Bond frozen in the Swinging Sixties. That is the core concept.

Literature

 * Patrick O'Brian's Aubrey-Maturin series had normal time for the first seven books-until the author realized he couldn't end the Napoleonic Wars yet and it remained 1813 for the next ten books, even though in one of them the narrative comments the characters have been away from England for "years." In the 18th book normal time resumed.
 * He referred to the years as "1812A, 1812B" and so on when speaking out of continuity.
 * Increasingly noticeable in the Ring Of Fire Shared Universe, where due to one-way Time Travel (of an entire town), the modern technology is from the 1999-2000 era.
 * To elaborate, the first book was published in early 2000 and was about an American town from the "present day" sent back to the year 1632. As the series has gone on for 10 years with many contributions by fans, writers and readers have sometimes failed to keep in mind that Grantville predates the ubiquity of many technologies like Google, iPods, cell phones, GPS systems and even DVDs. (While most of those existed in 1999, they weren't widespread and popular, especially not in relatively poor, rural areas.) If the series goes on for another 10 years, it won't be about "the present day" vs. "the start of the modern era", it will be about one historical period vs. another.
 * It helps that the inhabitants of Granville had to 'gear down' soon after their arrival in 1632 since their most advanced technology started breaking down and could not be repaired. So the level of technology after a few books is an Anachronism Stew and references to post 2000 technology can be generally avoided.
 * Sherlock Holmes, of course--originally set in the present day and treated as such until about World War II (with Basil Rathbone fighting Nazis in 1940); most later Holmes stories are set in the original time period.
 * Doctor Jekyll and Mr. Hyde is also typically adapted as taking place in Victorian England. Present-day stories may get around this by having the formula be rediscovered by a modern day descendant or researcher while keeping the original story in its original period.
 * Ditto for The Time Machine. This gives contemporary writers a good lead on the Time-Traveler, allowing him to pass through real time periods on his voyage to 802701 AD. Of course, a one hundred year lead isn't all that impressive when he's going 800,000 years into the future, but it's something. Both the 1960 film and the 2002 film give 1899 as the Time-Traveler's year of origin, which is actually four years after the novel was written. (The 1960 version goes so far as to make him take off from New Year's Eve of 1899, i.e. the last day of the 1800's.)
 * The time period of the Redwall series never moves beyond the Middle Ages, despite decades passing between almost every book.
 * Tarzan was originally set in the present day and was treated as such until about the 1980s. Around that time, the character started to get tied to The Edwardian Era in which he first appeared, something which may have been started by Greystoke: The Legend of Tarzan. The Disney version goes back further and sets itself in the time of Victorian Britain, which has pretty much codified in the public imagination that the story doesn't take place in the present.

Live Action TV

 * Perhaps the most egregious example of Frozen in Time was M*A*S*H, which ran for 11 years when the actual Korean War lasted less than three (and on average most surgeons only served about six months at a MASH.) There were at least four Christmases and six winters shown, and Alan Alda went from young and raven haired to middle aged and greying.
 * If anything, time moved backwards on this show. The season four episode "Change of Command", for instance, has Colonel Potter arriving to take charge of the 4077th on September 19, 1952; in season nine's "A War for All Seasons", he's shown (along with B.J. Hunnicutt, who arrived just before him, and Charles Winchester, who arrived well after him) welcoming in the year 1951 with the rest of the camp in flashback.
 * Combat, which covered the post-D-Day (1944-45) adventures of an infantry platoon ran from 1962-67.
 * Heartbeat ran for eighteen years, and when it ended it was still The Sixties.
 * Even worse than that, for the last decade or more of the show's run they were specifically stuck in 1969, a year in which Gina Ward managed to cram in two full-term pregnancies. And they don't seem to have made it past July.
 * Oddly enough, Happy Days was not Frozen in Time -- by the end of the series they had actually made it into the early 1960s, as had its spinoff, Laverne and Shirley.
 * On the other hand, both shows' laziness about period detail makes this something of a moot point at any rate.
 * The first episode of That 70s Show took place in May of 1976 and eight years later, the series finale took place on New Year's Eve 1979. Admittedly, four years in, That 80s Show was launched, but it was a bomb.
 * Also Eric & Co. go to see Star Wars midway through the first season, which didn't premiere until May 1977. The show stopped telling us the exact date shortly thereafter.
 * Possibly lampshaded at the beginning of the season 8, when the license plate shown at the end of every episode (and sporting the year the series' action takes place) was shown for a few episodes without a year on it, and Kitty referred to the current year as "nineteen... today" in the premiere.
 * 24 is an interesting variation on this, in that every episode is a specific hour in a specific day. Generally, the show's makers put great effort into making sure that costuming and makeup reflect this - an injury suffered in one episode leaves a bruise for the rest of the season, for example - but there is the occasional blunder. For example, in Phillip Bauer's second appearance on the show, near the end of season 6, his hair was considerably longer, and worn in a markedly different style, than he had had it in his first appearance (set 16 hours earlier, but filmed nearly 4 months prior.)
 * The TV series Gunsmoke, set in Dodge City, Kansas, in 1873, ran for twenty years without any noticable change in setting or costume. However, as might be expected, James Arness, Milburn Stone, and Amanda Blake all aged a considerable amount in those 612 episodes.
 * Allo Allo, set in Nazi-occupied France, lasted longer than the entirety of World War 2.
 * The Australian soap opera The Sullivans which was set during the Second World War, ran for 17 years, some 11 years longer than the real WW2.
 * Dads Army started with the formation of the Home Guard in 1940, and followed that plotline for its first season, with the platoon gradually gaining weapons and uniforms over the course of the season. The remaining eight seasons did not specify which year(s) the show followed (although events such as the arrival of the Americans in the war were mentioned), and the series ended with the war still in progress.
 * Hogan's Heroes - 6 seasons, all supposedly taking place between 1942 and 1945. Of course, most of these were not in chronological order anyway - historical background details in three episodes in the 5th season place the show at 1943, 1945, and 1944 in that order.
 * Inverted in historical dramas like Upstairs, Downstairs and The Duchess Of Duke Street, where two or three decades pass in continuity but the actors only age four or five years.

Newspaper Comics

 * Rupert Bear began in 1920 and is still published today. Its setting still appears to be sometime in the 1920s or '30s.

Theatre

 * A Chorus Line became trapped in The Seventies at some point in its original run (which extended all the way through the 1980s).