'''連続活劇'''（れんぞくかつげき、 ''serial'', or ''cliffhanger''）とは、1910年代-1920年代に流行した映画の形式である。10分-20分ほどの、アクションを主題にした短編映画で、毎週1本ずつ公開していき、約15本で完結した。現在の連続テレビドラマの最古の起源とも言える。

連続活劇はたいてい低予算で制作され、ヒーローが悪党と戦い、ヒロインを救出するという物語のアクション映画であった。

連続活劇の起源は、エジソンによる『メアリーに何が起こったのか』に始まったといわれている。

比較的最近の人気アクション映画にも、連続活劇の影響を色濃く受けているものが多い。

恋愛描写が非常にあっさりしているのも特徴で、出会えば簡単に恋に落ちる、という具合である。

==物語の特徴==

悪党は常にヒーローを殺そうと仕掛けてくるが、ヒーローは勇敢にもヒロインを助けに向かい続ける。そしてヒーローは彼女が殺されそうになっているギリギリのところで救い出す。また、今度こそは悪党を殺した、と思ったところで、悪党に逃げられてしまうこともある。

連続活劇が生み出した、アクション映画のお決まりのシチュエーションがある。

|thumb|right|DVD front cover for ''[[Adventures of Captain Marvel|The Adventures of Captain Marvel'', one of the most celebrated serials for both Republic Pictures and of the sound era in general.]]

'''Serials''', more specifically known as '''Movie serials''' or '''Film serials''', were animated cartoons, newsreels, and two feature films.

Most serials were Westerns, since those were the least expensive to film. Besides Westerns, though, there were films covering many genres, including crime fiction, espionage, comic book or comic strip characters, science fiction, and jungle adventures. Although most serials were filmed economically, some were made at significant expense. The ''Flash Gordon'' serial and its sequels, for instance, were major productions in their times.

Serials were a popular form of movie entertainment dating back to Edison's ''Arsene Lupin Contra Sherlock Holmes'', based upon the Maurice LeBlanc novel ''Arsene Lupin Contre Herlock Sholmes'', and a possible but unconfirmed Raffles serial in 1911<ref>According to information from [http://www.silentera.com Silent Era]</ref>. Usually filmed with low budgets, serials were action-packed stories that usually involved a hero (or heroes) battling an evil villain and rescuing a damsel in distress. The villain would continually place the hero into inescapable deathtraps and situations, or the heroine would be placed into a deathtrap and the hero would bravely come to her rescue, usually pulling her away from certain death only instants before she met her doom. The hero and heroine would face one trap after another, battling countless thugs and lackeys, before finally defeating the villain.

Many famous clichés of action-adventure movies had their origins in the serials. The popular term cliffhanger was developed as a plot device in film serials (though its origins have been traced by some historians to the Sherlock Holmes stories of Arthur Conan Doyle), and it comes from the many times that the hero or heroine would end up hanging over a cliff, usually as the villain gloated above and waited for them to plummet thousands of feet to their deaths. Other popular clichés included the heroine or hero being tied to a railroad track; being lashed to a log in a sawmill, lying on a conveyor belt and approaching a gigantic whirling sawblade; or being trapped in an abandoned mine shaft, watching as the burning fuse of a nearby bundle of dynamite sparked and sputtered its way towards the deadly explosive. The popular Indiana Jones movies are a well-known, romantic pastiche of the serials' clichéd plot elements and devices.

The silent era was the zenith of the movie serial and serial stars from this period were major stars such as The Perils of Pauline'' which still ranks among the best known silent films. Ruth Roland, Marin Sais, Ann Little and Helen Holmes were also early leading serial queens. Most of these serials put beautiful young women in jeopardy week after week. The serials starring women were the most popular during the silent period but in the sound era few serials had a female character in the major role.    
Years after their first release, serials gained new life at "Saturday Matinees," theatrical showings on Saturday mornings aimed directly at children. For that reason, serials are sometimes called "Saturday Matinee Serials," even though they were originally shown with feature films.  

In the early days of television in the United States, movie serials were often broadcast, one chapter a day. Many are now available on VHS tapes and DVDs for collectors.

==Eras==
thumb|right|Poster for ''[[The Perils of Pauline (1914 serial)|The Perils of Pauline'' (1914)]]
===Silent era===
Famous American serials of the silent era include ''The Perils of Pauline'' and ''Fox, and Universal. Several independent companies (for example, Western serials. Four silent Judex'' and the German ''Homonculus''.

===Sound era===
The arrival of sound technology made it costlier to produce serials, so that they were no longer as profitable on a flat rental basis. Further, the Great Depression made it impossible for many of the smaller companies which had turned out serials to upgrade to sound, and they therefore went out of business. Only one serial specialty company, Mascot Pictures was in fact able to make the transition from silent to sound filmmaking: Universal Pictures also kept its serial unit alive through the transition.

In the early 1930s a handful of independent companies tried their hand at making serials, but managed only two or three, including the once-prolific Weiss Brothers. The Weisses bought a little time when Flash Gordon'', the first serial ever to play at a major theater on Broadway; and by the success of that same year of the newly-created Republic Pictures, which dedicated itself to a program of serials and westerns, eschewing major productions in their favor. The creation of Republic involved the absorption of Mascot Pictures, so that by 1937, serial production was now in the hands of three companies only - Universal, Columbia and Republic, with Republic quickly becoming the acknowledged leader in quality serial product. Each company turned out four to five serials per year, of 12 to 15 episodes each, a pace which they all kept up until the end of World War II when, in 1946, Universal dropped its serial unit along with its B-picture unit and renamed its production department Universal-International Pictures. Republic and Columbia continued unchallenged, with about four serials per year each, Republic fixing theirs at 12 chapters each while Columbia fixed at fifteen.

By the mid-1950s, however, episode television series and the sale of older serials to TV syndicators by all the current and past major sound serial producers, together with the loss of audience attendance at Saturday matinees in general, made serial-making a losing proposition.

===Post-1950s serials===
There have been several attempts at serials post the 1950s.  The first, and most famous, was ''Captain Celluloid Vs. The Film Pirates'', released in 1966.  This was a four chapter silent serial shot on 16 mm in the style of the Republic mystery villain serials.  The plot involved a villain named The Master Duper, out to pirate copies of a complete version of Greed.  The Master Duper was one of three members of a Film Commission and the heroic Captain Celluloid was determined to uncover him.  The film is notable for having serial historians Alan G. Barbour and Willaim K. Everson in it.

In the 1970s, Blackie Seymour allegedly shot a complete 12 chapter serial called ''The Return of the Copperhead''.  Whether the film was really shot or not is debated to this day as all that seems to exist of it is a 3 minute trailer.  Seymour himself says he shot it all but never edited it.

On February 27, 1979, Cliffhangers!'', which had three segments, each with a different serial: a horror story (''The Curse of Dracula'', starring Michael Nouri), a science fiction/western (''The Secret Empire'', starring Geoffrey Scott as "Marshal Jim Donner" and Mark Lenard as "Emperor Thorval") and a mystery (''Stop Susan Williams!'', starring Susan Anton, Ray Walston as "Bob Richards" and Albert Paulsen as the villain "Anthony Korf"). Unfortunately, the series was cancelled and the last program aired on May 1, 1979 before all of the serials could conclude; only ''The Curse of Dracula'' was resolved.

In 2001 a new sound serial was shot on video, ''King of the Park Rangers'', or as it's more simply known KOTPR.  This was advertised as the first full length serial since 1956 and it does, in fact, run 12 chapters, most of them close to fifteen minutes.  It concerned the adventures of a Park Ranger named Patricia King who teamed up with FBI Agent Alan Blake to track down a trio of killers out to find the Buried Treasure of Captain Kidd in the New Jersey Pine Barrens.  The film was most notable for having the Jersey Devil as a subplot (though never actually showing the creature), something never before done in a serial.  The most common knock against it was that the credits were far too long.  In 2008, KOTPR was re-issued on DVD with a shorter credit sequence.  KOTPR was originally released in sepia, but the DVD release was straight black and white.

In 2006, Dark Horse Indie films through Image Entertainment released a 6 chapter serial spoof called ''Monarch of the Moon''.  Detailing the adventures of a hero named the Yellow Jacket, who could control Yellow Jackets with his voice), it was a goofy but fun film that found the hero battling Japbots and traveling to the moon.  It was released in both color and black and white versions, though the color was muted.  Former wife of WWE wrestler Diamond Dallas Page, Kimberly Page, gave a solid performance as one of the film's villains.  The end credits promised a second serial, ''Commie Commandos From Mars''.  Dark Horse attempted to promote the release as a just found never before released serial made in 1946 but suppressed by the US Government.  Most fans weren't fooled, however.

In 2008, the makers of KOTPR returned with a second serial, ''The Dangers of Deborah''.  This time the serial only ran 10 chapters and had a mystery angle as a fiesty female reporter and a criminologist fought to uncover a mysterious villain named The Terror, who was out to steal an invisibility formula.  Like ''KOTPR'', this was shot on video.

===Machinima Era===
In recent years there has been a small resurgence of a sort in serial production.  Many films created using three-dimensional rendering engines to create computer-generated imagery, have been distributed in serial format. According to Hugh Hancock of Machinima.com, three to five minutes is an optimal length for videos downloaded over the Internet. As a result, a serial composed of multiple short videos can be an effective way of telling a longer story in this medium. ''Red vs. Blue: The Blood Gulch Chronicles'', a comedy series by Rooster Teeth Productions with a continuous, single plot spanning 100 episodes, popularized this distribution method.<ref>Hancock, Hugh (November 23, 2004). [http://www.machinima.com/article.php?article=425 Editorial - Serialise This!]. Machinima.com. Retrieved 15 March 2006.</ref> Many ''Red vs. Blue'' episodes end with cliffhangers, and Rooster Teeth Productions has acknowledged that the series is similar to older film serials in this regard.<ref>Rooster Teeth Productions (2004). Audio commentary. In Red vs. Blue Season Two [DVD]. Buda, Texas: Rooster Teeth Productions</ref> Another notable machinima production, Edgeworks Entertainment's ''The Codex'', is a self-contained film, but was nonetheless released as a serial in 20 episodes between February and August 2005.

==Production==
===Peak form===
The classic sound serial, particularly in its Republic format, has a first episode of about 30 minutes (approximately three masked, secret, or unsuspected villain menacing an unspecific part of America. This episode traditionally has the most detailed credits at the beginning, often with pictures of the actors with their names and that of the character they play. Often there follows a montage of scenes lifted from the cliffhangers of previous serials to depict the ways in which the master criminal was a serial killer with a motive. In the first episode, various suspects or "candidates" who may, in secret, be this villain are presented, and the viewer often hears the voice but does not see the face of this mastermind commanding his "lead villain," similar to a sergeant, whom the viewer will see in just about every episode.

In the succeeding weeks (usually 11 to 14) thereafter, an episode nearer 20 minutes (approximately two reels) in length was presented, in which the "lead villain" and lesser thugs commit crimes in various places, fight the hero, and trap someone to make the ending a cliffhanger. Many of the episodes have clues, dialogue, and events leading the viewer to think that any of the candidates were the mastermind. As serials were made by writing the whole script first and then slicing it into portions filmed at various sites, often the same location would be used several times in the serial, often given different signage, or none at all, just being referred to differently. There would often be a female love interest of the male hero, or a female hero herself, but as the audience was mainly children, there was no hugging and kissing.

In 1938 Republic introduced the "economy episode" (or "recap chapter") in which the characters  summarize or reminisce about their adventures, so as to introduce showing those scenes again (in the manner of a clip show in modern television). This type of episode usually had a cheap, mechanical cliffhanger, like a time bomb rather than being unconscious in a runaway vehicle. 

The beginning of each chapter would bring the story up to date by repeating the last few minutes of the previous chapter, and then revealing how the main character escaped. Often the reprised scene would add an element not seen in the previous close, but unless it contradicted something shown previously, audiences accepted the explanation. On rare occasions the filmmakers would depend on the audience not remembering details of the previous week's chapter, using alternate outcomes that did not exactly match the previous episode's cliffhanger.

The last episode was sometimes a bit longer than most, for its tasks were to unmask the head villain (who usually was someone completely unsuspected), wrap up the loose ends, and end with a triumphal proclamation, followed by a joke — and sometimes a kiss (provided that the story supplied a heroine to receive it).