Episode Zero: The Beginning

Kyoko: River City Girls Zero? What's that?
Misako: It's a new game featuring us and our boyfriends. Well... not exactly new...
Kyoko: But I thought games started with the number 1 then went to 2...
Misako: It's our very first adventure together, released way back in 1994.
Kyoko: Woah, that's hecka old! How come I never heard about it?
Misako: It was only released in Japan until now.

— River City Girls Zero Gameplay Pre-Order Trailer

Putting "Zero" in the title of a work, or episode of that work, can be a good shorthand that a work is a prequel, prologue, or even a remake of a first chapter. Some comic book origin stories are shown in issues numbered 0.

Subtrope of Numbered Sequels. Compare Title 1. See also Unusual Chapter Numbers, Year Zero.

Note: If "Zero" is in the title for any other reason, it doesn't count (as it wouldn't be the beginning). So works like Mega Man Zero and Phantasy Star Zero wouldn't be an example. Also, the names have to be official, not fan nicknames.

---

Examples:

Anime & Manga

• Aika Zero is a prequel to Agent Aika.
• In Bleach, Chapter 0 is a prequel chapter taking place directly before the start of the series, such as Rukia being assigned to Karakura Town and Renji being promoted to lieutenant of Squad 6. Notably, flashback chapters are given negative numbers based on how long they are before the story, with larger numbers for chapters that are further in the past, so it makes sense that Chapter 0 would be immediately before the start of the story.
• Cardfight!! Vanguard had a manga adaption which had a Chapter Zero that showed how Kai first started playing Vanguard.
• Fairy Tail ZERØ showcases how the titular guild got started in the first place.
• Fate/Zero is a prequel to Fate/stay night.
• Fist of the North Star Zero: Legend of Kenshiro is an anime movie set during the one year gap after Shin took Yuria away from Kenshiro, but before the start of the manga.
• Ga-Rei -Zero- is a prequel to Ga-Rei.
• Ichi the Killer: Episode Zero, an animated prequel to the live-action film Ichi the Killer.
• Jujutsu Kaisen is technically a sequel to a one-volume monthly manga called Tokyo Metropolitan Curse Technical School. As the latter series became much better known, its predecessor was rereleased under the title Jujutsu Kaisen 0.
• When Kageki Shoujo!! was first released, it was serialized in Jump X magaine as Kageki Shojo! — one exclamation mark. The sequel manga, which added a second exclamation mark, would be serialized in Melody from 2015 onward, and when Hakushensha re-released the original Kageki Shojo! as a single tankōbon volume in 2019, it was retitled Kageki Shojo!! Season Zero (or Kageki Shojo!! The Curtain Rises).
• Lupin III:
  • Lupin III: Episode 0: First Contact shows (one version of) how Lupin and the gang first met each other. The franchise usually relies on, at best, Broad Strokes continuity, so Unreliable Narrator is to be expected.
  • Lupin Zero is a take on Lupin and Jigen's teen years, expanding on flashback chapters from the original manga.
• Lyrical Nanoha:
  • In Magical Girl Lyrical Nanoha Movie First The Comics, the chapters depicting events that may have occurred before the movie itself were called Sequence 0-X, where X is the chapters of Sequence 0.
  • Magical Record Lyrical Nanoha Force had Chapter 0, which served as a short prologue for the manga.
  • Magical Girl Lyrical Nanoha INNOCENT started with Duel 00, which served as an introduction to this Alternate Universe of Nanoha and the "Brave Duel" card game that this Spin-Off will revolve around.
• Macross Zero, a prequel to the original Super Dimension Fortress Macross.
• Mobile Suit Gundam Wing: Episode Zero.
• My-Otome 0: S.ifr, a prequel to the other My-Otome films.
• One Piece: Chapter 0 serves as the backstory for many pivotal events, such as Roger's old rival Shiki and his role in the canonical film Strong World.
• Queen's Blade Rebellion Zero, a manga, althrough technically an interquel between the events of the QB's OVAs and the gamebooks' continuity version of Rebellion.
• Rose Hip Zero is a prequel to Rose Hip Rose.
• SD Gundam Force Emaki Musharetsuden Zero was a prequel to SD Gundam Force Emaki Musharetsuden.
• Saint Seiya has a movie titled Saint Seiya: Episode 0, which is Not an Example of this trope, as it's actually a Clip Show movie recapping the seasons preceding the Hades Chapter. However, there is also a short manga with the same name which chronicles events before the show began, better fitting this trope.
• Space Patrol Luluco has the Drama CD track "Episode 0.5", detailing how Luluco's parents' relationship went from a cute romance to all-out warfare at the breakfast table while their kid is present.
• Steel Angel Kurumi 0, a prequel to the Steel Angel Kurumi series.

• The film Un-Go: Episode 0, prequel to Un-Go.

Comic Books

• The Flash: Season Zero is a comic book prequel to Season 1 of The Flash (2014).
• Marvel Comics had a "Flashback Month" in which every comic published an #-1, set before the origin stories.
  • More specifically, in most cases they were set before Fantastic Four #1, which started the Silver Age of Marvel.
• "Chapter 0: Of Ducks, Dimes, and Destinies", part of The Life and Times of Scrooge McDuck. It covers the same events as Chapter 1, showing Magica's involvement via time travel; it was actually written earlier, but not published for some time to avoid having such similar stories come out too close together.
• Ninja High School received a Chapter 0, many years after it first began. It was an Interquel for Ichi-kun (after her grandfather defeated her in Chapter 1, but before her trip to America) and Asrial (after she was made aware of who she was being sent to marry, but before being transformed into a human form), but a Prequel for Jeremy (showing him the day before his introduction in Chapter 1).
• Paperinik New Adventures started with no less than three number zeros, titled 0, 0/2 and 0/3 respectively, which introduced the series' main characters and concepts. A few years later issue 0/1 was also published, detailing how Paperinik adjusted to his new life after the events of issue 0.
• In an interesting use of this trope and Unusual Chapter Numbers, every volume of Resident Alien begins with an issue #0 normally, as if #0 were the actual #1.
• Spider-Girl's first issue was numbered 0, and was a reprint of What If? v2 #105, the issue she first appeared in.
• Robert Crumb's Zap Comix came out with an issue 0: he had lost the art to the first issue and made a new one, then discovered the missing artwork and released it later.
• "Zero Month" following DC Comics' Zero Hour: Crisis in Time! is a borderline case; the #0s all retell the heroes' origins, but in Flash Back, with a Framing Story in the present.
  • There was another "Zero Month" for the one-year anniversary of the New 52 reboot.
    • Before the New 52, there was an Issue #0 of Batwoman, which consists of Batman observing the heroine to get confirmation on her identity, eventually deeming her a worthy candidate for Batman Inc. It is included in the collected edition of the comic's first storyline. Funnily enough, this means that Batwoman has two Issue #0s in this continuity.
    • Averted with in Green Lantern #0 and Green Lantern: The New Guardians #0; featuring new present-day origins (of Earth's newest Green Lantern and an overhauled New Guardians roster) instead of flashbacks.
  • The New 52 version of Bruce Wayne first taking on the Batman identity is titled Batman: Zero Year.

Fan Works

• Always Visible: The work begins with act zero, which actually increases the number of parts to four.
• Psychedelic Epiphany Series: Yearly Epiphany: The first chapter, Year 0: Hearthswarming Epiphany, about the beginning of the first year, or zeroth year, of Epiphany's life.
• Vow of Nudity: A prequel story starring Haara's mother is numbered 0 despite being the third story published. Spectra's first story is also labeled 0 because it takes place before she becomes a level 1 warlock.
• The Monster Rancher fanfic Episode 0: Before the Beginning is a fan-made prequel to the anime.

Film

• The Slit-Mouthed Woman 0: The Beginning.
• Cube Zero is the third film in the series but is a prequel to the first film.
• No Game No Life, has a prequel movie titled No Game No Life Zero that focuses on the world being a terrible war zone centuries before the heroes arrive. It adapts the sixth light novel.
• Ring 0 Birthday. A prequel to the Japanese film Ringu.
• Yoshie Zero, a prequel to Mutant Girls Squad. A rare example where the non "zero" part of the title doesn't match the sequel.

Literature

• Princesses of the Pizza Parlor: Cookies and Campers starts with "Session 0 (Wednesday Before)", a prologue before the main story.

Live-Action TV

• Kamen Rider Drive Episode 0: Countdown to Global Freeze is Exactly What It Says on the Tin - the events precceding Roimund's first attack on the world.
• Kamen Rider Snipe: Episode ZERO shows the first outbreak of Bugster virus and Taiga's hopeless fight against it that led to him becoming a Fallen Hero
• Mashin Sentai Kiramager: Episode ZERO shows the recruitment of the first four Rangers. Unlike most examples of this trope, the movie was actually released first, premiering a month before the TV series.
• Pretty Guardian Sailor Moon Act Zero, a prequel to Pretty Guardian Sailor Moon.

Video Games

• Ace Combat Zero: The Belkan War, prequel to Ace Combat 5: The Unsung War and the entire series by extension (barring maybe the original game, which takes place at an unspecified time the same year the Belkan War is set).
• Blaster Master Zero is a reimagining of the Nintendo Entertainment System game Blaster Master, but is actually a Stealth Sequel to the Japanese Metafight series.
• Danganronpa:
  • Danganronpa Zero is the Light Novel prequel to Danganronpa: Trigger Happy Havoc.
  • Chapter 0 of Danganronpa 2: Goodbye Despair is a brief scene that occurs before the events of the game began.
• Dark Void Zero. Originally starting out as an April Fools joke based off of an 8-bit rendition of Dark Void's main theme, the game soon became a fully-fledged DSiWare title claimed to be a "legendary 'lost project'" of Capcom's, recently found locked away in their vaults.
• The Dating Sim Dream Club Zero, a prequel to Dream Club.
• While never officially called that by the big N, the first entry in the Mother series was (and still is) often called “EarthBound Zero” by fans. It got that honorary title, since due to it being the prequel to the game that actually released as EarthBound, which is helped by its late export.
• Final Ninja Zero is a prequel to Final Ninja.
• Ko-ko-ro...0 is the third game in the Ko-ko-ro... H-Game series to be released, but the events of Ko-ko-ro...0 precede those of Ko-ko-ro... and Ko-ko-ro...II. Though incest and rape are primary themes in the series as a whole, one of the possible endings of Ko-ko-ro...0 (namely, the revelation that Kasumi is Souji's mother, not his older sister) dials up the squick factor of the already quite squicky original game.
• Master Detective Archives: Rain Code opens with Chapter 0 to show the protagonist Yuma's journey to Kanai Ward, the game's main setting, rather than starting at the prologue after he's already arrived.
• Metal Gear Solid V: Ground Zeroes is a standalone prologue to Metal Gear Solid V: The Phantom Pain that was sold separately and sets up the plot for the main game. Subverted by both Metal Gear Solid 3: Snake Eater and Metal Gear Solid V itself, which are both prequels to the original Metal Gear Solid (and by proxy, the MSX2's Metal Gear), but are numbered by their release order.
• Metroid: Zero Mission is a remake of the first Metroid game.
• Perfect Dark Zero, a prequel to Perfect Dark.
• Record of Agarest War Zero, prequel to Record of Agarest War.
• Resident Evil 0, starring Rebecca Chambers of S.T.A.R.S. Bravo Team prior to the Spencer Mansion incident.
• River City Girls Zero: An entry in the Kunio-kun series that shows the time Kunio and Riki went together with Misako and Kyoko to prove their innocence. In this case, this is a Market-Based Title due to this game only being localized after River City Girls, which was the playable debuts for Misako and Kyoko for most of the world.
• Samurai Shodown V, a prequel to the original game, was titled Samurai Spirits Zero in Japan.
• Silent Hill: Origins has the "O" in its subtitle stylized to look like a zero; it was retitled Silent Hill Zero in Japan.
• Star Fox Zero, which serves as the second Continuity Reboot of the Star Fox series.
• Star Revenge 0: Galaxy of Origins, a prequel to the whole series.
• The Street Fighter Alpha series is titled Street Fighter Zero in Japan. While actually set after the original Street Fighter, the plot of the Alpha series (at least for the first two games) explores the events that led to the Street Fighter II tournament (namely Chun-Li's pursuit of M. Bison and Charlie's death).
• Submachine Zero: Ancient Adventure, which is set before the original Submachine.
• Trinity: Souls of Zill O'll is titled Trinity: Zill O'll Zero in Japan.
• Yakuza 0 is a prequel to the Yakuza series, set 17 years before the first game.
• While "Ultima 0" was originally just a Fan Nickname for Akalabeth, the title was made official when it was included in the Ultima Collection compilation box.
• Zork Zero: The Revenge of Megaboz. The ninth and final Zork game released and a prequel to the original.

Visual Novels

• Although Steins;Gate 0 is nominally a sequel to the original Steins;Gate, heavy use of Alternate Timelines and Time Travel brings a few prequel elements into the mix, with the "0" in the title pulling double-duty as an infinite loop.

Web Animation

• 24: Day Zero. A series of animated webisodes. It's a prequel series, focusing on Jack Bauer's first 18 months at CTU.
• TOME has Episode 00: /File:Zero. It focuses on the Netkings rather than the main players and showcases the Netkings as they first make the game and inadvertently play a hand in the creation of the Forbidden Power by introducing negative emotions to the core of the game, SOFDTI.

Webcomics

• Aurora (2019) begins with Chapter 0 (or, as it's formatted on the website, Arc 0) consisting of 3 strips telling some of the strip's very distant backstory.
• On the Origin of PCs, the first The Order of the Stick prequel, was published as issue number 0. Start of Darkness, the second prequel, takes place even earlier, so it's issue number -1.
• Station Square's prologue chapter is Episode 0.
• xkcd's print edition starts with volume 0. It's not a prequel, the author just likes zero-indexing.
• After shaking off some Early-Installment Weirdness, the author of Megatokyo decided to break the story up in to chapters. Rather than retroactively label what he made until then as Chapter 1, he decided to plan out the chapters starting with 1, with everything before that being Chapter 0.

Web Videos

• Carmilla has a prequel season, Season 0, set in 2012, before Laura comes to Silas in the first season proper, set in mid-2014 (when the webseries actually started airing).
• Freeman's Mind released an Episode 0 between 34 and 35, showing Gordon going through the hazard course and refusing to finish after being told to jump two stories onto concrete.

Western Animation

• The Codename: Kids Next Door television movie, Operation: Z.E.R.O., begins with showing the events behind the foundation of Kids Next Door. The acronym even stands for "Zero Explanation Reveals Origins."

Other

• Sometimes, video streaming platforms will place collections containing pilots or bonus material of a established work in its own tab and label it as "Season 0" of said work.
• Apple released the Apple Watch in 2015, then the second generation models were sold as the Series 1 and Series 2. The first model is often known as the "Series 0".

---