Plot immunity

Plot immunity is a phenomenon in fiction (particularly serialized fiction, such as television series and comic books) that allows for major characters – usually the protagonist and/or antagonist – to avoid the consequences of events that would remove them from the plot. The most common variation of this is the protagonist's seeming invulnerability to fatal consequences. Killing the hero would end the story without resolution. Audience awareness of this "immunity" drains the dramatic tension, as they know that the main character won't die in the middle of the first act. The result is the hero being locked in a deathtrap while the audience yawns or laughs.

One way in which a story might work around this is by causing a form of near-fatal injury or consequential setback to the "immune" character. Another is to kill a supporting character, particularly one which the audience has likely grown fond of (for example, the sidekick or love interest, or the hero's pet dog); the sacrifice of "redshirts" do not convince the readers that the main characters are in actual danger of even emotional harm.

Role-playing games have an additional problem regarding immunity. Fatal consequences for a player character are a way of keeping the player's goals down to earth. If the character is never perceived as being in any danger, then the player will never surrender or back down from any adversary or obstacle, regardless of how ridiculous it might seem to do so. On the other hand, character death leaves the character's player with nothing to do in the game for the remainder of the session; a good gamemaster is able to find balance between these two extremes.

Cases of exception to plot immunity

Some authors have found that killing a central character perceived by the audience as "immune" to death due to the nature of the piece is a powerful plot device. Some character deaths that fall into this category include:
*Within the first half of the film "Psycho", Marion Crane, seemingly the protagonist at the beginning of the story, is famously killed off in the shower scene. This may be one of the most famous examples of a defiance against the convention of plot immunity, as it shocked much of its original theater audience.
*The same method is used in "The Departed", in which almost every major cast member is killed off in a sudden and cold way, including Leonardo DiCaprio's part.
*Nick Andros, a protagonist in Stephen King's "The Stand".
*In Dan Simmons' novel "Summer of Night", the seeming protagonist is killed early in the book.
*Spock in "" (but was revived in the following movie)
*Data in "Star Trek Nemesis" (but a similar role survived by his 'brother', B-4, also played by Brent Spiner)
*Carson Beckett and Elizabeth Weir, protagonists in the TV series "Stargate Atlantis".
*Joss Whedon killed off Jesse McNally, seemingly a main character, in the second episode of the TV series "Buffy the Vampire Slayer".
*Wash and Book, protagonists in the movie "Serenity" and tv series "Firefly".
*The television series "Lost" is an exception to Plot Immunity, as many of the lead characters, who were thought to be critical to the storyline, were killed off.
*The television series "24", where many key characters have died, including the protagonist's wife.
*The cartoon ExoSquad, where Deleon (a main character and second in command, intelligence officer) was killed off in a battle, without any heroic fanfare even. Many other main characters in ExoSquad were also killed off as well (both human and NeoSapien).
*In "Executive Decision", Steven Seagal's character is killed off within the first 10 minutes of the movie - despite being listed on the movie and in advertisements as a main character of the movie, and being set up as a conventional action hero in the film up to this point (playing on Seagal's established type). The other main character, played Kurt Russell, has a character shield, despite being an unconventional action hero type.
*In "L.A. Confidential", the same token is used when Jack Vincennes (played by nominal star of the film Kevin Spacey) is killed by the villain in a sudden, anticlimactic way before the film's main showdown.
*In "", Sergeant Paul Jackson, a playable character is killed in a nuclear explosion less than half way into the game.
*The television series "" was known for frequently killing off main characters (actually having the original star die after a single season). It should be noted, however, that this was frequently due to an unwillingness of the production staff to re-negotiate contracts when actors demanded more money.
*The film "No Country For Old Men", based on the "novel" of the same name, develops the apparent protagonist (played by Josh Brolin) in great detail, only to have him murdered off-camera mid-film. This recenters the film on what originally appeared to be a secondary character, played by Tommy Lee Jones. The story also breaks with convention in that this character acts in a way that provides minimal plot resolution.
*George R. R. Martin is known for the killing off of many named and important characters in the "Song of Ice and Fire" series.