Indeed, some fans would probably prefer to forget it. The series was done with the best of intentions, aiming to clear up various inconsistencies caused by the landmark Crisis on Infinite Earths. It promised to consolidate the inconsistent future timelines of the DC Universe into a new unity.
The architect of the cosmic upheaval was Hal Jordan, who, mad with grief after the destruction of his home town of Coast City, and having obtained immense power as Parallax, attempts to destroy and then remake the universe.
Or course, Hal dies in the end, but like the whole Zero Hour series, it can be looked on as a monumental waste of time. Hal’s back again in the current universe, which of course has been diverged and converged into yet another entity, until such time as future DC Comics chief call for another reboot.
One of the main victims of Zero Hour was the Legion, which was forced to undergo a restart after Superboy and Supergirl were eliminated from DC continuity, with Mon-El recast as Valor to take Superboy's place as the Legion's inspiration and most powerful member.
Promotional materials issued for Zero Hour featured some members of the Legion. There were two separate posters issued for the event: one included Lightning Lad and Ultra Boy with his ponytail, the other showed Jo in his Emerald Dragon guise. Go figure.
Promotional advertisements and folders for Zero Hour in the fan press also included Legionnaires (see images below).
One interesting piece of merchandise given away to retailers was a Zero Hour clock, featuring various characters including Andromeda and Vril Dox.
|Zero Hour poster with Lightning Lad and Ultra Boy.|
|Zero Hour poster with Emerald Dragon (Ultra Boy).|
|Fan press advertisement for Zero Month.|
|The Zero Hour clock.|
Bits Boy runs the comprehensive Legion completists’ site Bits of Legionnaire Business.