Stand Alone Episode

An episode that can stand alone on its own with a self-contained story that does not need prior viewing of any other episode to understand. It's usually an episode that breaks from the current Arc to focus on a one-shot subplot or character; for example, if the arc is about stopping The End of the World as We Know It, a Stand Alone Episode can be about dealing with a Sealed Evil in a Can that's released at the beginning of the episode and resealed by the end of the episode, never to be mentioned again.

A Stand Alone Episode can also be a Beach Episode, Breather Episode, or A Day in the Limelight, but not always; the only prerequisite of one is not to follow a script that goes on for more than one episode. When such an episode happens to be a Season Finale, it is a Denouement Episode.

Many shows can be considered a long run of Stand Alone Episodes. Comedy series usually consist entirely of Stand-Alones because each episode usually focuses on a different gag or zany schemes. Likewise, Adventure Towns series generally consist of Stand Alone Episodes.

In arc-heavy series, a good Stand Alone Episode can be the hook a die-hard fan of the show can use to pull others in, due to its self-contained nature. Likewise, even fans of the arcs will often cite a Stand-Alone as their favorite episode; an arc episode is difficult to separate and appreciate outside of the arc which contains it, but a Stand Alone Episode can be fully appreciated of itself.

Sometimes, though, writers will want to revisit the plot of a Stand Alone Episode and create a later episode that expands on the earlier story; this is a Sequel Episode.

By their very nature, the pilot episode for a show is usually a Stand Alone Episode.

Compare Filler, although the label is usually only used when a stand-alone episode isn't really good enough to stand at all.

Anime and Manga

 * Ghost in the Shell: Stand Alone Complex actually labeled its stand-alone episodes (as opposed to arc-based "complex" episodes) as such on the title card. SAC: 2nd Gig did the same, but labeled its stand-alone episodes as "dividual" as opposed to the other two types ("individual" and "dual").
 * Digimon will often lead up to the climax of an arc, then have one episode of pure Filler before the dramatic stuff begins.
 * Parts 4 and 5 of Jojo's Bizarre Adventure are considered to be stand-alone, as they have little-to-nothing to do with the main story (Parts 1, 2, 3, and 6).

Live Action TV

 * The X-Files "Clyde Bruckman's Final Repose" and many others. "Humbug," "The Host," and "Jose Chung's From Outer Space" to name a few.
 * Babylon 5 "Passing Through Gethsemane"
 * Not totally, the B plot regarding Lyta and Kosh hints at the fact that
 * The West Wing "Isaac and Ishmael" - possibly the only Stand Alone Episode in the whole series, and explicitly stated to be outside the regular series continuity.
 * "The Long Goodbye" arguably counts. Though there are phone calls to Toby re: the current arc one or two times, the episode is otherwise entirely about CJ dealing with her Alzheimer's-stricken father. It's also one of the few episodes of the first four seasons not to be written by Aaron Sorkin. This all makes it very much Love It or Hate It.
 * Lost 's sixth season has the universally acclaimed "Ab Aeterno," which focuses solely on . Because 90% of the episode takes place and focuses little on the main characters, it has been praised as a good "gateway episode" to introduce someone to Losts format and mysteries without actually starting them from scratch and the closest thing Lost has to a TV movie (the episode is extended by six minutes).
 * Red Dwarf: "Psirens" was specifically written as a "reintroduction" episode for the series, through Lister's amnesia sequence.
 * Millennium: "Somehow, Satan Got Behind Me".
 * The Doctor Who episodes Love and Monsters and Blink have nothing to do with the overall story arc, and both focus on normal humans who encounter the Doctor.
 * The Deep Space Nine episode The Visitor is often ranked as one of its best episodes, even though most of it takes place in an alternate future timeline, and the main character is a guest star (Tony Todd) playing the now-elderly Jake Sisko.
 * The Stargate SG-1 episode Window of Opportunity could be viewed as this.

Video Games

 * Mass Effect 2's loyalty missions have little to do with the main plot of the game, instead focusing on the squadmate characters.

Western Animation

 * Teen Titans and its Breather Episodes, often at the end of a dramatic arc.