There are thousands of movies in the horror genre family. With a large number of sub-genres on it, a viewer can find a great diversity of topics to enjoy: Zombies, Killers, Haunted Houses, Giant Monsters, Cannibal tribes…

In this article the reader (and hopefully horror fan) would be able to find a general structure that is shared among a big majority of the films that represent this genre.
As happens with any cultural or literature piece, this is a subjective structure that represents in some way how horror movie plots are composed. There are no blacks or whites in this appreciation so, feel free to elaborate your own ideas.

In the history of horror films, exists a lot of interesting documents, books and researches about the horror genre. The following material is created through an extensive compilation of readings, documentaries and also podcasts of reference to help in the elaboration of this article.

Introduction:

The horror genre is one of the most prolific ones in the history of cinematography. Since its creation, we can find several examples in it’s early pieces, like Le Manoir du diable (1896) by the French director and illusionist Georges Méliès.

The source of the material for this genre comes directly from the Gothic fiction, with authors of reference that, in the future, will define the genre and also, see their pieces represented through the years.
Some figures of relevance in these beginnings are Mary Shelley (Frankenstein), Bram Stoker (Dracula),  Washington Irving (The Legend of Sleepy Hollow) and multiple works from Edgar Allan Poe and H.G. Wells among other writers.

When the film studios started to arise, horror titles began to attract a lot of viewers to the screens. The professionals of the industry, initiated a race to elaborate the best adaptations from theatre plays, novels or even the creation of new content in order to fill the niche that was emerging.

A film starts with a script, and it needs some sort of structure. Analysing the genre, one can find some common structures that can be found in almost all the genre titles or, at least, some components or blocks that are used and reused on thousands of them.
Noel Carroll in his book “The Philosophy of Horror: Or, Paradoxes of the Heart” define perfectly an archetypical series of structures that form an horror movie.
This basic skeleton is formed in four pieces:

• The onset.
• The discovery.
• The confirmation.
• The confrontation.

They are not compulsory, sometimes they happen simultaneously and also, they can appear multiple times, like the discovery and confrontation.
Let’s take a look at them.

The onset (or beginning): 

This is the starting point where the horror tale starts because the presence of the monster is established in one of the two following ways:
– The monster is revealed immediately (like in thrillers).
– The effects of the monster are revealed (like in mystery plots)

In Jaws (1975), the movie starts immediately revealing the existence of the monster in the first scenes, where we can see a girl swimming in the sea, being attacked by some sort of marine creature. This plot follows the common structure of the thrillers, unveiling the monster directly to the viewer.

In Alien (1979), the first time that we are aware of the existence of the monster is in the scene were the explorers found the dead corpse of “The Navigator“. When they realized that something explode from the inside and following up, a big hole on the floor its shown. This way to unveil the monster corresponds to the second way described, close to how the mystery plots begins.

The discovery:

At this step, the character/s are aware about the existence of the monster. The discovery can happen several times by different subjects because it can iterate through the film.

Elizabeth, the role played by the actress Mae Clarke on Frankenstein (1931), is the archetype of character discovering the monster in an horrific way. 
It’s common the combination of horror and/or disgust at the moment of the discovery and also, it’s also known as “the scream” moment by obvious reasons.

The discoveries that occur on the Saw franchise use to be the announcement of bad news for the characters. In Saw (2004), one of the victims of “Jigsaw” discover about the existence of the monster by the following way:

The confirmation:

In this act, the discoverers convince or help other “unbelievers” on the existence of the monster. The most characteristic example is when the main characters approach the Police Station / Armed Forces, several times without success but, something happens clearly that unveil the true nature of the monster.

A good example of confirmation and, at the same time, discovery, can be shown on The Descent (2005) were the protagonists discover the existence of the monster and, at the same time, confirms it’s existence.
                                                               *** SPOILERS AHEAD ***

The confrontation:

It’s clear that this step consists in the fight again the monster. Typically, several attempts (confrontations) are needed until it’s finally defeated and some support characters will die on the way as they confront the monster.
On this phase, the concepts of “final girl” and the way to the sequels are defined.
As the amount of material regarding the confrontation part it’s paramount, some examples are described below.

                                                               *** SPOILERS AHEAD ***

Final thoughts:

This schema can be found in thousands of examples but it’s not a canon that is established in all the genre, there are also hundred of examples with combination of part of the elements.

The onset and the confrontation are almost fixed components that can be found in the majority of the horror movies. Sometimes, the onset, happens at the same time as the discovery, when the viewer unveils the existence of the monster at the same time as the characters on the film.
With other movies, like Godzilla (1954), there is no discovery because on the onset, is assumed that Godzilla is an entity known by all the characters so, after the monster is presented (onset), the confirmation follows up.
As described previously, it’s easy to find movies that had discovery and confirmation in the same scene because, as seeing is believing, discovery and confirmation are bound in some plots.

There are some specific plots in horror that are out of this schema or, because the specificity of the sub-genre, had an special a structure like the Mad Doctor sub-genre that will be defined in future articles.