A television format similar to a series of Mini Series. Rather than airing a self-contained episode each week, long stories are broadcast broken into a number of individual parts.
This format derives from the serial format used by the short films once shown before a feature, and, before that, the publication of novels in magazines. (Many of the works of Charles Dickens and Arthur Conan Doyle were originally published as serials.)
The modern Cliffhanger evolved from the custom of ending most episodes of a serial with a suspenseful scene which left our heroes in peril (often, literally hanging off a cliff).
All the episodes of a story are usually considered as a single unit. In syndication or video release, they may be edited together into a "movie format" which stitches the episodes together, usually removing the Cliffhanger.
Differs from the Soap Opera in that the narrative is not continuous throughout the entire series. Typically, each story would last between three and eight episodes then end.
Differs from a Story Arc in that each episode is not a complete story on its own. Though the format is not mutually exclusive of a Story Arc, continuity between episodes which are not part of the same story is generally minimal (though this is probably entirely a result of arcs having been rare when the serial format was common).
For some reason, this format was particularly common for British science fiction series.
- Doctor Who (used throughout the 1963-1989 Classic Series; dropped in the 1996 telemovie and the 2005-present revival series, save for 2009's "The End of Time")
- The Tomorrow People (1973)
- Sapphire and Steel
- The Bill since 2002
- Many British sci-fi shows that did this are also examples of British Brevity, where the whole season is one serial but very short:
- Rocky Jones, Space Ranger
- On radio, Yours Truly Johnny Dollar during the late 1950s, as well as Superman and lots of other shows.
- Dr. Kildare (TV show) used this format for it's fifth and final season.
- Ghost Hunt is an example that's rare both for being anime and for happening in 2006-2007.
- Black Lagoon is another modern anime example.
- Moonlight Mask
- The Space Giants (a.k.a. Ambassador Magma)
- The CW's Arrowverse has been doing this since 2016 — first that year with the Invasion! (2016) event, told over four installments (as episodes of Supergirl, Arrow, The Flash, and Legends of Tomorrow) over two nights. Crisis on Earth-X followed in 2017. 2018 saw the three-part Elseworlds (the Legends sat this one out, to reduce the behind-the-scenes logistics; however, Batwoman appeared as a backdoor pilot for her own show, and the Barry Allen of the early 1990s Flash series appeared for the first time since his show was cancelled). Finally, there came Crisis on Infinite Earths (2019) — an adaptation of the comic event which saw an epic, multiverse-threatening event — and the requisite number of cameos to back it up, from all over DC media (including, much to everyone's shock, the DC Extended Universe version of The Flash); the Crisis unfolded across five shows, as well as a Red Skies Crossover episode of Black Lightning (who then proceeded to join the other heroes beginning in part 3, and whose Earth, along with Supergirl's Earth-38, was amalgamated with the main Arrowverse Earth, Earth-1, into a singular "Earth-Prime") .
Sometimes used as a format for one segment within a Variety Show:
- The namesake segments of Rocky and Bullwinkle.
- Mathnet on Square One TV
- The Bloodhound Gang on 3-2-1 Contact
- Around the World in 79 Days on The Cattanooga Cats.