Following George Pérez and Marv Wolfman's classic Crisis on Infinite Earths, the DC Universe started anew with a blank slate, allowing new creators to tell fresh new stories unhindered by 50 years' worth of continuity. This was back in 1986. Fast forward eight years later, and the DC Universe has become as complex as it ever was.

Dan Jurgens was roped in to write and draw this sequel, in an attempt to clear up all the remaining continuity glitches such as the aforementioned Hawkman problem, as well as allowing the Legion of Super-Heroes to start anew.

The story opens with the apparent death of the Time Trapper at the hands of a mysterious assailant in the end of time. There, this mystery villain brings forward the end of all that is by bringing the entropic energy into the past. This phenomenon is first discovered by Matthew Ryder of the Linear Men and Metron of the New Gods. Fearing the worst, Ryder sends colleagues Waverider and Rip Hunter to investigate, while Metron attempts to warn the various heroes of the DC Universe.

Waverider and Rip Hunter appear in the 63rd century, only to see Wally West a.k.a. Flash die in a failed attempt to stop the entropy. They journey further back to the 58th century also only to see Hal Jordan fall victim. The Linear Men suffer a loss at this point with the death of Rip Hunter, with his final moments commanding Waverider to search through the Linear Men archives for a "crisis".

Meanwhile, time anomalies start appearing as Joker, Batman and the current Robin encountering a healthy, mobile Batgirl, as well as a young Dick Grayson parading around in a Robin costume. The immortal Vandal Savage sees Hawkman morphing into various incarnations of himself, all without the knowledge of the latter. Alan Scott, the original Green Lantern is mysteriously de-aged. Superman encounters multiple versions of Batman. Superboy bumps into a young Clark Kent who calls himself Superboy. These, and many more occurrences are happening at an increasing rate even as the entropic forces rips time apart at both the beginning and at the end of time.

Waverider assembles the members of the original Justice Society of America to battle Extant, the mysterious villain responsible behind this mess, even as Superman brings together a huge assembly of heroes at the behest of Metron. The JSA's battle with Extant is tragic and utterly final as he single-handedly defeats the JSA, rapidly aging them to their natural ages, resulting in the deaths of Dr Fate and Hourman, Wildcat suffering a cardiac arrest, and the original Green Lantern's powers removed. These tragedies forces Waverider to warp the JSA back to Metropolis for their safety. Here, in what is undoubtably the most poignant and touching moment in Zero Hour, the JSA decides to retire, as the assembled heroes stand in silence as they watch the original heroes walk quietly into the night.

Determined to stop Extant as well as the time rifts at all costs, the heroes split into two teams to stop both time rifts. Unfortunately, the heroes' success is only temporary as another mysterious figure re-opens the rifts in the 30th century. As the time rifts pop up all over the place, one by one the heroes fall, beginning with those hailing from the future such as Impulse and Booster Gold, and those who were born centuries ago, such as Dr Mist.

As time begins to unravel and only 60 seconds remaining in the life of the universe, the true villain reveals himself by punching Superman's lights out. He is revealed to be Hal Jordan, ex-Green Lantern of Earth. Even as the remaining heroes stand in shock, time fades away and the universe ceases to exist.

Waverider whisks the heroes away to Vanishing Point, headquarters of the Linear Men and a place where time does not exist. Here, Waverider formulates a plan with Superman, Hawkman, Green Arrow, Captain Atom, Damage, Ray, Green Lantern, Donna Troy, and Atom to stop Hal Jordan and save the universe. Aided by the Spectre, the heroes launch an all out assault on Hal Jordan, draining him of the energies he gained when he destroyed the Green Lantern Corps main power battery back in Green Lantern vol.3 # 50. Weakened but still powerful enough to accomplish his goals, his one-time best friend Green Arrow is forced to shoot an arrow into Jordan's chest, killing him. WIth the immediate threat subdued, the heroes and Spectre pour all their energies into the energy-channeling Damage to start the Big Bang anew, allowing nature to recreate the universe as it was meant to be, and all anomalies resulting from Crisis on Infinite Earths removed from the time stream.

Waverider transport the heroes back to 20th century Metropolis, with all those who died earlier none worse the wear. Still, the victory is not without it's price, and no one pays it heavier than Oliver Queen who was forced to kill the man who he considered his own brother.

Was this a satisfying a read as Crisis on Infinite Earths? Definitely not. In fact, very few changes happened as a result of Zero Hour In fact, apart from allowing the Legion of Super-Heroes to start anew, nothing of importance actually happened. Hawkman became an amalgamation of all previous versions, suddenly transforming into a winged mutant with avian eyes and natural wings, confusing the heck out of readers and writers alike.

Unfortunately, the story is only mediocre at best, and rather formulaic in execution. The deaths of the various characters were neither shocking nor the least bit thrilling as we all knew they would be resurrected and returned to normalcy by the end of the story. The only major surprise was the revelation that Hal Jordan was the actual villain of the story, instead of Extant. Events such as Power Girl giving birth to a baby boy or the betrayal of the Team Titans are long since forgotten in the annals of continuity.

A lot of the things mentioned in the story, such as Batman and Superman going through bad years, Aquaman's wounded hand, and the nature of Extant and Waverider's relationship, would be familiar to regular readers of DC Comics, but would prove confusing to new readers as these litle throwaway lines were not expanded or explained upon. It is this dependence on the readers' familiarity with other events happening in other DC titles that hinder it's accessibility. There were also no mention on what the Crisis was, or what happened between the Joker and Batgirl, among others.

This is partially due to the length allotted for this story. Unlike the year-longCrisis on Infinite Earths, Zero Hour was released in five weekly instalments. By limiting it to only five issues, Jurgens is forced to pack too many details into a scant 100+ pages, a third of the length of Wolfman's epic. As such, Zero Hour is merely a formulaic and forgettable crossover.