Question: A quest serves as a plot device in mythology and fiction: a difficult journey towards a goal, often symbolic or allegorical, which word, that refers to the sequence of events inside a story which affect other events through the principle of cause and effect?

Context articles: Technology in science fiction
Group mind (science fiction)
Invisibility in fiction
Quest
Mind control in popular culture
Plot (narrative)
Genetic chimerism in fiction
Caspar David Friedrich
Plot device
MacGuffin

Technology in science fiction examines the possibilities and implications of new technologies.
 Authors have taken, or created, new innovations and technologies, and elaborated on what they might be and how they might be used.
 This exchange goes in both directions – sometimes the technology appears first in science fiction, then becomes reality (such as space travel) and other times the real technology comes first, and science fiction authors speculate about how it might be used, and how it might affect the human condition.
 Likewise, the accuracy of the technology portrayed spans a wide range – sometimes it is existing technology, sometimes it is a physically realistic portrayal of a far-out technology, and sometimes it is simply a plot device that looks scientific, but has no basis in science.
 Examples drawn from space travel in science fiction include:
A group mind, hive mind, group ego, mind coalescence, or gestalt intelligence in science fiction is a plot device in which multiple minds, or consciousnesses, are linked into a single, collective consciousness or intelligence.
 Its use in literature goes back at least as far as Olaf Stapledon's science fiction novel "Last and First Men" (1930).
 A group mind might be formed by any fictional plot device that facilitates brain to brain communication, such as telepathy.
Invisibility in fiction is a common plot device, found in both the science fiction and fantasy genres.
 In fantasy, invisibility is often invoked and dismissed at will, with a magic spell, a potion or a ring.
 In science fiction, invisibility is often conferred on the recipient as part of a complex process that is difficult or impossible to reverse, so that switching back and forth at frequent intervals is less likely to be done in science fiction.
A quest serves as a plot device in mythology and fiction: a difficult journey towards a goal, often symbolic or allegorical.
 Tales of quests figure prominently in the folklore of every nation and ethnic culture.
 In literature, the object of a quest requires great exertion on the part of the hero, who must overcome many obstacles, typically including much travel.
 The aspect of travel allows the storyteller to showcase exotic locations and cultures (an objective of the narrative, not of the character).
 The object of a quest may also have supernatural properties, often leading the protagonist into other worlds and dimensions.
 The moral of a quest tale often centers on the changed character of the hero.
Mind control has proven a popular subject in fiction, featuring in books and films such as "The Manchurian Candidate" (1959; film adaptation 1962) and "The IPCRESS File" (1962; film 1965), both stories advancing the premise that controllers could hypnotize a person into murdering on command while retaining no memory of the killing.
 As a narrative device, mind control serves as a convenient means of introducing changes in the behavior of characters, and is used as a device for raising tension and audience uncertainty in the contexts of Cold War and terrorism.
 Mind control has often been an important theme in science fiction and fantasy stories.
 Terry O'Brian comments: "Mind control is such a powerful image that if hypnotism did not exist, then something similar would have to have been invented: the plot device is too useful for any writer to ignore.
 The fear of mind control is equally as powerful an image."
Plot refers to the sequence of events inside a story which affect other events through the principle of cause and effect.
 The causal events of a plot can be thought of as a series of sentences linked by "and so".
 Plots can vary from simple structures such as in a traditional ballad to complex interwoven structures sometimes referred to as an "imbroglio".
 The term "plot" can serve as a verb and refer to a character planning future actions in the story.
Human genetic chimerism, which can not only cause a wide range of illnesses but also lead to the same person having more than one profile in genetic fingerprinting, has served as a plot device in many works of fiction.
 Most known examples are subsequent to the 2004 book "Free Culture", where author Lawrence Lessig digresses briefly to describe chimerism and suggest that it could, and had yet to, be well used as a television plot device (particularly for police procedurals involving genetic fingerprinting).
Caspar David Friedrich (5 September 1774 – 7 May 1840) was a 19th-century German Romantic landscape painter, generally considered the most important German artist of his generation.
 He is best known for his mid-period allegorical landscapes which typically feature contemplative figures silhouetted against night skies, morning mists, barren trees or Gothic or megalithic ruins.
 His primary interest as an artist was the contemplation of nature, and his often symbolic and anti-classical work seeks to convey a subjective, emotional response to the natural world.
 Friedrich's paintings characteristically set a human presence in diminished perspective amid expansive landscapes, reducing the figures to a scale that, according to the art historian Christopher John Murray, directs "the viewer's gaze towards their metaphysical dimension".
A plot device, or plot mechanism, is any technique in a narrative used to move the plot forward.
 A contrived or arbitrary plot device may annoy or confuse the reader, causing a loss of the suspension of disbelief.
 However a well-crafted plot device, or one that emerges naturally from the setting or characters of the story, may be entirely accepted, or may even be unnoticed by the audience.
In fiction, a MacGuffin (sometimes McGuffin or maguffin) is a plot device in the form of some goal, desired object, or other motivator that the protagonist pursues, often with little or no narrative explanation.
 The MacGuffin's importance to the plot is not the object itself, but rather its effect on the characters and their motivations.
 The most common type of MacGuffin is a person, place, or thing (such as money or an object of value).
 Other more abstract types include victory, glory, survival, power, love, or some unexplained driving force.