The 1994 sequel to Crisis on Infinite Earths and second of the many reality-warping Crisis Crossovers to hit The DCU. Written and illustrated by Dan Jurgens, with inks by Jerry Ordway. It was published as a weekly.
Just as Crisis removed The Multiverse 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, 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 Big Bad of an earlier Crisis Crossover, Armageddon 2001. However, it turns out that Extant was actually working on the orders of none other than the former Green Lantern 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 by his design 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.
Zero Hour resulted in a few significant changes to The DCU, most notably the introduction of the "post-boot" Legion of Super-Heroes. It also spawned a few Spin-Off series, including Fate, Manhunter, Primal Force, Xenobrood and 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 Cosmic Retcon of The DCU and the first "proper" sequel to Crisis on Infinite Earths, 2005's Infinite Crisis.
No relation to the airline disaster movie on which Airplane! is based, the German dub title of Future War 198X, the expansion pack of Command & Conquer: Generals, the third After Hours season of I'm a Marvel... and I'm a DC, or the short-lived drama series on ABC.
This story provides examples of:
- Advancing Wall of Doom: The entropy rifts.
- Alternate Universe/Alternate Self: Part of the story involved characters dealing with these, including Batman and Robin meeting the original Golden Age Alfred, Batman seeing a world where Joe Chill didn't kill his parents, Superman meeting alternate Batmen, Superboy meeting the original Superman-as-a boy Superboy, Superman seeing a world where he died as a baby and the Kents are still young, and most notably, a Batgirl from a world where the Joker killed Sal Maroni before he could scar Harvey Dent and, in an alternate version of The Killing Joke, killed Jim Gordon instead of crippling Barbara (with Dent replacing Gordon as Commissioner and Joker ultimately scarring Dent himself). Tim Drake!Robin teams up with Dick Grayson!Robin in Robin #10.
- All There in the Manual: Batman #511 details the backstory of the alternate Batgirl seen throughout the event proper: in her world, the Joker didn't cripple Barbara — instead he murdered Commissioner Gordon. This Joker also killed Sal Maroni before he could disfigure Harvey Dent, Dent himself went on to replace Jim as Commissioner and institute a "kill vigilantes on sight" order, Barbara and Bruce are lovers, either Dick or Jason is still Robin (as the alternate Barbara notes Tim's age), and the Joker also disfigured Dent himself during the issue.
- Apocalypse How: A Class X-4. Parallax wipes out all existence in the universe with the entropy rifts. Only several heroes survive, some which were transported to Vanishing Point outside of space and time, and some ended up appearing with Parallax in the Blank White Void.
- Big Bad: Parallax.
- Big Damn Heroes: 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 to kickstart his Super-Power Meltdown and save history.
- Birth/Death Juxtaposition: Power Girl's child is born shortly after the alternate universe Batgirl dies and is then erased from existence.
- Blank White Void: The universe itself is turned into a very large one in issue #1 after Hal Jordan as Parallax has finished erasing it with his entropy rifts, in which only a few surviving heroes get to witness him recreating the universe.
- Call-Back: The time-erasing wall is similar to the anti-matter wave from Crisis on Infinite Earths.
- Canon Discontinuity: The subplot about Power Girl giving birth seems to have been dropped from continuity.
- Close-Enough Timeline: Near the end of #0, the heroes triggered a new Big Bang, which created a new timeline, albeit with subtle differences compared to the previous one.
- Continuity Snarl: Hawkman's ties to this story are partly part of the problem with his snarl.
- Cop Killer: As noted above, the alternate version of Barbara Gordon's Batgirl seen throughout is from a reality where the Joker decided to kill her father instead of crippling her.
- Cosmic Retcon: 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.
- Curb-Stomp Battle: Extant vs. the Justice Society of America. The JSA didn't stand a chance.
- Death by Depower: Extant kills several members of the JSA by removing the slowed-down aging powers they gained in the 1940s, causing them to suffer from No Immortal Inertia.
- Death Is Cheap: Pretty much everyone who wasn't Damage or Parallax died during the event—and outside of most of the Justice Society of America, came back by the end.
- The Dragon: Extant.
- Dropped a Bridge on Him: DC editorial didn't care for the JSA at the time, and used the event as an excuse to get rid of them. The original Doctor Midnight, Atom and Hourman are killed off outright, while Doctor Fate, Jay Garrick, Wildcat, Starman, Sandman, Johnny Quick and Johnny Thunder are forcibly restored to their proper physical ages, turning them into a bunch of geezers. Most of them retire, with Starman straight up saying he's too old to keep on fighting the good fight. Kent and Inza Nelson (the two halves of Doctor Fate) survived the story, only to be immediately killed off in the new Fate series that spun out of it, with DC instead replacing him with a younger, edgier '90s Anti-Hero named Jared Stevens. The other problem was Comic-Book Time: the JSA at the time still had the same age as superheroes who are at that point 40 years younger.
- Early-Bird Cameo: Issue #1 features the first cameo appearance of Jack Knight, the son of Starman, who would soon go on to star as the protagonist of James Robinson's iconic Starman run.
- Energy Absorption: Extant in his still-human form of Hank Hall absorbs the energies of the Waverider in his Fusion Dance to become the final form of Extant.
- Era-Specific Personality: In Superman: The Man of Steel #37, Superman met multiple versions of Batman, including (and transforming into) the following artists' renditions: the 70s Neal Adams incarnation, The Dark Knight Returns incarnation (including the Mutants), the original 30s Bob Kane incarnation, Kelley Jones, Dick Sprang, and Carmine Infantino.
- Et Tu, Brute?: The Team Titans are revealed to be alternate timeline puppets of Extant in this series.
- Fallen Hero: Extant and Parallax. More so with Parallax given that he was still shown to be a very much aware well-intentioned Hal Jordan driven to madness out of grief and desperation to restore his home city and repair the damage done to his life.
- The Fourth Wall Will Not Protect You: The last few pages of the penultimate comic were blank white pages. Similarly, all tie-in issues released the same week had blank pages.
- Fountain of Youth: The Ray Palmer Atom gets regressed to an 18-year-old when he attempts to get inside Extant.
- Fusion Dance
- 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.
- Future Me Scares Me:
- The original Waverider finds out that he would eventually become part of Extant when the villain reveals his true face before the Fusion Dance takes place later on.
- The original Cosmic Boy finds out that his future self would become the Time Trapper. But he eventually comes to grips with that possible future and lets the Time Trapper help where he could during the time crisis.
- Go Mad from the Revelation: Waverider was horrified when he learned about the Crisis.
- The Gods Must Be Lazy: When Metron asks The Spectre for help, he sends the New God away, thinking that the crisis is natural in nature. When Jay Garrick approaches him, he decides to help and ruefully admits that peering through time is beyond his scope.
- Green-Eyed Monster: Kenny Braverman, who'd always been second best to Clark Kent.
- Heroic BSoD: Green Arrow breaks down in grief after the fight with Parallax.
- Heroic Sacrifice: The alternate universe Batgirl, throwing herself between Parallax and Damage.
- In Their Own Image: Parallax wants to eliminate all pain and suffering. If that means destroying the universe to create a new one, so be it.
- Internal Homage: 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.
- Kill 'Em All: Parallax's tampering with time sends out a wave of entropy that destroys reality across all past, present, and future timelines, killing countless people across all of history. The only people who initially survived were those who were present at the dawn of time where Parallax was destroying everything.
- Last Kiss: Lightning Lad and Saturn Girl share a final kiss together before they fade into the unknown — a Shout-Out to a similar scene with Alexander Luthor and his wife Lois Lane of Earth-3 in Crisis On Infinite Earths.
- Long Title: Though referred to as just Zero Hour, the official title is Zero Hour: Crisis in Time!, though the covers make it out to be The End of Today... Zero Hour: Crisis in Time.
- Minimalistic Cover Art: Issue #0 has just the title of the comic book on the cover.
- Mood Whiplash: The Nothing Is Scarier blank pages ending tie-in issues were immediately followed by ads, diluting the intended effect.
- My Hero, Zero
- The Man Behind the Man: Parallax.
- Near-Villain Victory: Parallax pretty much succeeds by the end of the story. The universe is wiped out, and the heroes can't stop him, since he's the only one with the power to fix it, even if it would be iin his image. The heroes allow him to start the process, but stop him to let it play out naturally.
- Original Generation: Triumph and Alpha Centurion get introduced in this series.
- Other Me Annoys Me: The two Superboys of separate timelines fight it out with each other until they both realize what is going on.
- Passing the Torch: A not-so-heroic one: The remaining Justice Society members retire after Extant's Curb-Stomp Battle, 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.
- Post-Climax Confrontation: Green Lantern #0 acts as an epilogue, showing Kyle taking on Parallax after the end of the main story.
- Rapid Aging: Extant used his powers to age most of the Justice Society members to their proper physical ages, some even to their deaths.
- Red Skies Crossover: Tie-in issues varied heavily in relation to the event, with Action Comics having all of Metropolis fading, while Detective Comics had a lighthearted throwback with Batman and Robin meeting the Golden Age Alfred.
- Retcon: Later writers walked back the severity of Extant's aging attack on the JSA. While a few like Sandman and Johnny Thunder were too old and feeble to continue their crime-fighting careers, the Starman series revealed that those were the ones who'd taken the brunt of the attack. The other survivors like Jay Garrick and Wildcat had only been been aged a few decades, with Ted Knight speculating that they were likely physically in their late 50s or early 60s at the absolute oldest.
- Ret-Gone: Once the new timeline restarted, all alternate realities ceased to exist. As a result, Alpha Centurion and the alternate Batgirl fade away. Though the mainstream universe's Alpha Centurion does show up eventually.
- Screaming Birth: Power Girl with her child, whose birth is being attended to by Wonder Woman.
- Set Right What Once Went Wrong/Utopia Justifies the Means: Parallax's ultimate goal, from preventing the Coast City tragedy, restoring the Green Lantern Corps, and was about to give Extant and the JSA their own Earths, an Earth where Batgirl and Alpha Centurion have their own Gotham City and Metropolis, respectively (essentially, restoring the Pre-Crisis Multiverse), and Superman a Krypton that never exploded.Parallax: In my universe, everything will be as it should... everybody wins!
- Stable Time Loop: When Damage resets the timeline, Waverider must prevent this to restore history. He does this by merging the point where Parallax tried to erase history fully to the point where Green Arrow strikes Parallax with Kyle Rayner holding Hal back. He attempts to rescue Kyle, but it happens too fast.
- Stripped to the Bone: Extant's attack on the Leymen in #1 reduces them to skeletons.
- Super-Power Meltdown: Damage in the final battle.
- Taking Up the Mantle: The mainstream universe's Matthew Ryder becomes the new Waverider when the original Waverider from Armageddon 2001 is fused with Monarch to become Extant.
- Time Crash: With multiple timelines and alternate selves appearing while the entropy rifts devour the universe from both ends of the space-time continuum.
- Time Travel:
- In the main series itself, Waverider and Metron send two groups to two different periods of time, one to the 30th century and the other to Earth's distant past, to try shutting down the entropy rifts. Metron's team succeeds while Waverider's team fails, with Waverider being overpowered by and merged with Extant. However, their efforts ultimately fail, as Parallax reopens the entropy rift in the future.
- In one of the side stories related to this event, Supergirl, Steel, Guy Gardner, and Batgirl are sent traveling forward through time, witnessing the events that led up to Coast City's destruction, with Guy having a final meeting with his former love Kari Limbo before she was destroyed with the city.
- Unusual Chapter Numbers: The first issue is numbered 4 and counts down to issue 0.
- Well-Intentioned Extremist / Woobie, Destroyer of Worlds: Parallax.
- What Happened to the Mouse?: Wally and Kyle's fates are revealed in their respective 0 issues.
- You Can't Make an Omelette...: Used by Hal Jordan as Parallax to justify the erasure of the universe in order to create a new universe where, say, Superman's Krypton never blew up and Captain Atom never lost eighteen years of his life to become the hero.
- This is just the beginning!