[[quoteright:300:http://static.tvtropes.org/pmwiki/pub/images/Zero_Hour_1_2656.jpg]]
[[caption-width-right:300:"I've seen the universe from many different directions, and I know how to fix it -- [[WhatTheHellHero even if it means destroying it!]]"]]
->"It's over. Your time is over. ''All'' time is over. '''This is ''[[TitleDrop Zero Hour.]]'''''"
-->-- '''[[Comicbook/GreenLantern Paralax]]'''

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]].
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!This story provides examples of:
* AdvancingWallOfDoom: The entropy rifts.
* BigBad: Parallax.
* CanonDiscontinuity: The subplot about PowerGirl giving birth seems to have been dropped from continuity.
* CosmicRetcon
* CurbStompBattle: Extant vs. the JusticeSocietyOfAmerica. The JSA didn't stand a chance.
* TheDragon: Extant.
* FallenHero: Extant and Parallax.
* HeroicBSOD: GreenArrow breaks down in grief after the fight with Parallax.
* MinimalisticCoverArt: Issue #0.
* MyHeroZero
* TheManBehindTheMan: Parallax.
* 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).
* SuperPowerMeltdown: Damage in the final battle.
* TimeCrash
* UnusualChapterNumbers: The first issue is numbered 4 and counts down to issue 0.
* WellIntentionedExtremist / WoobieDestroyerOfWorlds: Parallax.
* WhatCouldHaveBeen: Years after Zero Hour had been finished, Alex Ross proposed a limited series entitled ''Batboy''. Based off the Super-Sons imaginary story from the 1970s, ''Batboy'' featured an idealistic future of the DCU, with Batboy and his best friend Superman Jr. as the main characters. The original JLA would've been retired, with the Comicbook/TeenTitans now comprising the League. Other heroes would be Batwoman (Barbara Gordon) and Superwoman (Kara Zor-El), Barry Allen's kids the Tornado Twins, and Aquaman's still-living son, Arthur Jr.. The Joker would still be active, only with a teenage daughter by his side. Harvey Dent would've been cured of his psychosis and acting as a tutor for Bruce Jr., who would have a baby sister named Helena. The only still active member of the original League would've been Hal Jordan. How this ties into ''Zero Hour'' is that Batboy would've realized this world seemed too ideal, and would discover that, this was the end result of Hal's attempt to remake the DCU, and would confront him on it. Character designs and plot information for this series were released in Ross's art book ''Rough Justice''.