With the timestream restored, it's back to the future for the incredible origin of the 30th century's greatest heroes. As the free worlds of the galaxy take their first tentative steps toward unity, multibillionaire R.J. Brande looks for a way to repay the universe for his lifetime of prosperity.
Zero Hour Tie In
Ayla, Garth and Mekt have sneaked out their parents new cruiser for a joy ride around space, however the cruiser runs out of charge forcing the trio to land on Korbal for repairs. The three then attempt to lure a herd of lightning beasts to the ship to recharge the capacitor, however before the plan can be seen through Garth awakens from his dream. He then finishes packing preparing to leave Winnath following running away from home, while on Braal two time MagnoBall champion Cosmic Boy boards a shuttle heading for Titan. While on Titan the Science Police bring three girls to Saturn Girl as she attempts to find out their guilt, but is quick to prove there innocence and learns of the owners attempts to sell them on the black market. She quickly subdues the criminal and earns the right to join the Science Police. Meanwhile on the shuttle Garth takes his seat next to Cosmic Boy, while Saturn Girl and several other V.I.P.S. board the shuttle on the trip to Earth. However upon docking in the Metropolis space port, Saturn Girl picks up thoughts of murder from the three attending maintenance workers as they prepare to murder R.J. Brande. However the team of Cosmic Boy and Lightning Lad quickly disarm and take the team quickly down.
Reporters and Science Police are quick on the scene and begin interviewing the famous Cosmic Boy, while Garth quickly slips away to stop his mother from learning he's now on Earth. Meanwhile R.J. meets with President Chu Earth gov contacts to discuss his newest idea, to united the fledgling United Planets under a new rallying symbol. While at Science Police headquarters Saturn Girl is learning of her new responsibilities as a cadet under a bigoted captain, when Luornu Durgo arrives with a message from R.J. Brande. while elsewhere Cosmic Boy struggles in his practice as his manager continually taunts him until Luornu arrives with his message. While in jail Garth deals with the advances of several criminals in his prison cell following his arrest for asking to many questions, however he is bailed out just in time by Luornu. The three are then brought to R.J. Brande's officer and told to wait, during which Saturn Girl alerts Cosmic Boy to his managers gambling problem which has been using Cosmic Boy's earnings to cover. He then flies into a rage and prepares to attack her, but is stopped by Garth's intervention and then fired by Cosmic Boy who lets him know he is turning him in, as the office door opens. They are then met by hologram shrines towards Superman, Batman, Wonder Woman and the Flash he then offers the three the chance to become a "Legion of Super-Heroes" which all three accept, while elsewhere a shadowed figure plots another attempt on Brande's life.
- Superman, Batman, Flash and Wonder Woman appear as holograms.
- The story continues in Legionnaires #0.
- "DC Universe 20" one page Zero Hour advertisement featuring the front page of the Daily Planet with the headline "Zero Hour for Earth?"
- "DC Universe 21" a one page memorial dedicated to Neal Pozner. Artwork of three headshots of Neal by Phil Jimenez.