[[caption-width-right:300:"I've seen the universe from many different directions, and I know how to fix it -- [[FinalSolution even if it means destroying it!]]"]]
->"It's over. Your time is over. ''All'' time is over. '''This is ''[[TitleDrop Zero Hour.]]'''''"
-->-- '''[[Comicbook/GreenLantern Parallax]]'''

The 1994 sequel to ''CrisisOnInfiniteEarths'' and second of the many reality-warping {{Crisis Crossover}}s to hit TheDCU. Written and illustrated by [[TheDeathOfSuperman Dan Jurgens]], with inks by Jerry Ordway.

Just as ''Crisis'' removed TheMultiverse from the DCU, ''Zero Hour: Crisis in Time'' was intended to fix the many confusing alternate timelines that had cropped up over the previous decade. And also like ''Crisis'', ''Zero Hour'' failed, making everything involved--{{Supergirl}}, {{Hawkman}}, ComicBook/{{Legion of Super-Heroes}} -- even more confusing. ''Zero Hour'' was unique in that it started with issue #4 and worked its way back to #0; to coincide with the final issue, every ongoing DC series published a special "Issue Zero".

The plot of ''Zero Hour'' begins with the apparent death of the Legion's nemesis, the Time Trapper, at the hands of an unknown assailant at the end of time. After this event, the future history of Earth gets wiped out "in reverse", eventually including the Legion's 30th century home. Meanwhile, the past is also getting wiped out, with walls of entropy converging on the present. (How any of this is possible is an exercise left to the reader.)

At first, the villain of the piece appears to be Extant, formerly the hero known as Hawk, who had been the BigBad of an earlier CrisisCrossover, ''Armageddon 2001''. However, it turns out that Extant was actually working on the orders of none other than the former Comicbook/GreenLantern Hal Jordan, aka Parallax, who had gone mad with grief after the destruction of his home of Coast City. Parallax wanted to remake the universe in his image to prevent Coast City's destruction and other tragedies. His former comrades, deciding that a better universe isn't worth the destruction of the old one, fight Parallax and defeat him, triggering a new Big Bang and restoring the timeline--with a few differences.

Unlike its predecessor, ''Zero Hour'' met with poor reception, largely due to its lackluster execution. Plot points were thrown in with no build-up, some important events occured in tie-in issues rather than the main story itself, and the whole thing was mired in the DarkAge of {{Nineties Anti Hero}}es. The story's saving grace was the conflict surrounding Hal Jordan's actions and the heroes' response to seeing their friend become a villain, but that occurred almost entirely in the final issue and wasn't enough to salvage it.

''Zero Hour'' resulted in a few significant changes to TheDCU, most notably the introduction of the "post-boot" ComicBook/{{Legion Of Super-Heroes}}. It also spawned a few SpinOff series, ranging from the awful ''Fate'' and ''Manhunter'', to the [[SoOkayItsAverage aggressively mediocre]] ''Primal Force'' and ''Xenobrood'', to the critically-acclaimed and long-running ''Comicbook/{{Starman}}''.

In the end, ''Zero Hour'' hasn't been forgotten by DC--it remains in continuity, or at least it did until the {{New 52}} --but its events have been swept under the rug and mostly reversed. The problems it introduced were among the factors that led to the next CosmicRetcon of TheDCU and the first "proper" sequel to ''CrisisOnInfiniteEarths'', 2005's ''InfiniteCrisis''.

No relation to the airline disaster movie on which ''Film/{{Airplane}}'' is based, the German dub title of ''FutureWar198X'', the expansion pack of ''CommandAndConquerGenerals'', the third After Hours season of ''ImAMarvelAndImADC'', or the [[Series/ZeroHour short-lived drama series on ABC]].
!This story provides examples of:
* AdvancingWallOfDoom: The entropy rifts.
* BigBad: Parallax.
* BigDamnHeroes: The Spectre drops in at the very end to battle Parallax. Unlike the first Crisis, the Spectre is able to fend off Parallax long enough for him to be weakened, then gives Damage an extra boost kickstart his SuperPowerMeltdown and save history.
* BirthDeathJuxtaposition: Power Girl's child is born shortly after the alternate universe Batgirl dies and then is erased from existence.
* CallBack: The time-erasing wall is similar to the anti-matter wave from ''Crisis on Infinite Earths''.
* CanonDiscontinuity: The subplot about PowerGirl giving birth seems to have been dropped from continuity.
* CosmicRetcon: A large number of them. The two big prevalent ones being the reboot of the Legion of Super Heroes and that Joe Chill was never caught, thus making the case of who killed the Waynes a Cold Case.
* CurbStompBattle: Extant vs. the JusticeSocietyOfAmerica. The JSA didn't stand a chance.
* TheDragon: Extant.
* EtTuBrute: The Team Titans are revealed to be alternate timeline puppets of Extant in this series.
* FallenHero: Extant and Parallax.
* FountainOfYouth: The Ray Palmer Atom gets regressed to an 18-year-old when he attempts to get inside Extant.
* FusionDance
** Monarch and the original Waverider combine to form Extant.
** The Golden Age Hawkman and Hawkgirl merge with the modern-day Hawkman and the Hawk God to form the Post-Zero Hour version of Hawkman.
* FutureMeScaresMe: The original Waverider finds out that he would eventually become part of Extant when the villain reveals his true face before the FusionDance takes place later on.
* GoMadFromTheRevelation: Waverider was horrified when he learned about the Crisis.
* HeroicBSOD: GreenArrow breaks down in grief after the fight with Parallax.
* HeroicSacrifice: The alternate universe Batgirl, throwing herself between Parallax and Damage.
* LastKiss: Lightning Lad and Saturn Girl share a final kiss together before they fade into the unknown -- a ShoutOut to a similar scene with Alexander Luthor and his wife Lois Lane of Earth-3 in ''Crisis On Infinite Earths''.
* MinimalisticCoverArt: Issue #0.
* MyHeroZero
* TheManBehindTheMan: Parallax.
* OriginalGeneration: Triumph and Alpha Centurion get introduced in this series.
* PassingTheTorch: A not-so-heroic one: The remaining Justice Society members retire after Extant's CurbStompBattle, with Superman noting that things aren't going to be the same.
** In a more specific example, Ted Knight passes on the role of Starman to his son David, which eventually leads to his other son Jack becoming Starman in his own series.
** And Alan Scott symbolically passes on the role of Green Lantern to the recently-recruited Kyle Rayner.
* RapidAging: Extant used his powers to age most of the Justice Society members to their proper physical ages, some even to their deaths.
* SetRightWhatOnceWentWrong[=/=]UtopiaJustifiesTheMeans: Parallax's ultimate goal, from preventing the Coast City tragedy, restoring the Green Lantern Corps, and was about to restore the Pre-Crisis Multiverse (or at least it was implied).
* ShoutOut: The Wally West Flash disappearing out of his clothes during his attempt to shut down the entropy rift in the future is one for Barry Allen doing the same when he was attempting to destroy the Anti-Monitor's anti-matter cannon in ''Crisis On Infinite Earths''.
* SuperPowerMeltdown: Damage in the final battle.
* TakingUpTheMantle: The mainstream universe's Matthew Ryder becomes the new Waverider when the original Waverider from ''Armageddon 2001'' is fused with Monarch to become Extant.
* TheyWastedAPerfectlyGoodPlot: DC could have used the series as a way to restore [[ComicBook/{{Hawkman}} Katar and Shayera]]'s Silver Age history and undo most of the character's ComicBook/PostCrisis DorkAge stories.
* TimeCrash
* UnusualChapterNumbers: The first issue is numbered 4 and counts down to issue 0.
* WellIntentionedExtremist / WoobieDestroyerOfWorlds: Parallax.