Part of the advertising for the original Crisis On Infinite Earths, but could just as easily apply to the JLA/JSA team-ups that were an inspiration for DC's Crisis.
Time for a second look back at the team-ups of the Justice League and Justice Society, and all the varied Crises that brought them together.
The Super-Crisis That Struck Earth-Two
Four criminals on Earth-2 were suddenly found by Black Spheres and granted incredible powers, enough for them to be menaces to be handled by the Justice Society of America. Robin and Wildcat faced the Smashing Sportsman (Marty Baxter), Wonder Woman fought Gem Girl (Claire Morton), Hawkman and Mr. Terrific battled the Money Master (Horace Rowland) and Hourman faced How Chu the Chinese Bandit....but all the JSAers lost. Johnny Thunder showed up and sent his Thunderbolt against them, who also failed. He then had the T-Bolt bring 4 JLAers into the fight....and they also failed. The Thunderbolt was able to explain (after Johnny asked) that the Black Spheres were ultra evolved lifeforms from another dimension, who ended up here to escape their dying universe....and grafted onto these four humans. But, how would the combined JLA and JSA members defeat their foes?
The Negative-Crisis On Earths One-Two
The Thunderbolt gathered the remaining energies of the Black Spheres and put them in the JLA's Flash (Barry Allen) and Green Lantern (Hal Jordan) and JSA's Wonder Woman and Hourman, but....while giving them the power to fight the other villains, also turned them evil. The others JSAers along with the JLA's Superman and Green Arrow, had to fight their possessed friends, as well as the other villains, eventually defeating them.
This set of stories was the JLA debut of the Earth-2 Wonder Woman, as well as the first appearance of the Earth-2 Robin in the Silver Age, with Hourman coming fresh off his Showcase appearances with Dr. Fate. This was also the last JLA/JSA story illustrated by Mike Sekowsky.
The Stormy Return Of The Red Tornado
To be fair, this wasn't a return of the original Red Tornado, but an android (with no face under his mask) with wind based powers who wanted to join the JSA. Black Canary, Starman, Hourman, Dr. Fate and the Flash (Jay Garrick) deal with the Red Tornado, and take him along to face attacking faceless androids, which the heroes drive off, but with all but Dr. Fate thrown into a coma. Calling in the JSA's Atom, Sandman, Green Lantern (Alan Scott), Mr. Terrific, Dr. Mid-Nite and Hawkman, who are defeated by a program triggered in the Red Tornado by one of the faceless android's weapons. The villain behind this is revealed as T. O. Morrow...who had previously faced Flash (Barry Allen) and Green Lantern (Hal Jordan), who was doing all this to defeat the Justice League.
T. O. Morrow Kills The Justice League -- Today
Energy duplicates of Steve Trevor, Mera, Jean Loring, Hawkgirl and Midge, take out their respective paramours (Wonder Woman, Aquaman, Atom, Hawkman and Snapper Carr) at JLA HQ, with Superman, Batman, Flash, Green Lantern and Green Arrow facing creatures created by T. O. Morrow, then Amazo, Dr. Light, the Crystal Creature, Starro and Super-Duper...eventually defeating the heroes. But, the android Red Tornado on Earth-2, finds his way to Earth-1, gets the better halves of the JLA to revive those members. With them, they defeat T. O. Morrow, revive the rest of the JLA, as well as the JSA, with Red Tornado finally finding out he was created by T. O. Morrow as a part of his plan.
Reddy wonders what will happen to him now (which was joining the JSA), with the JLA bidding farewell to writer Gardner Fox (and seeing the start of Dick Dillin's incredible run on the Justice League of America).
Star Light, Star Bright -- Death Star I See Tonight
The JSA (with Dr. Fate, Wonder Woman, Green Lantern, Dr. Mid-Nite, Superman, Starman, Black Canary and Red Tornado; along with Black Canary's husband, Larry Lance) faced the living star, Aquarius. This being was exiled from his people, and had gone mad, attacking Earth. The heroes were captured, with only Red Tornado escaping, with Dr. Fate sending him to the JLA for help.
Where Death Fears To Tread
Aquarius hypnotizes the JSA into battling the JLA, with Batman fighting Dr. Mid-Nite, Atom and Flash vs. Dr. Fate, Hawkman (E-1's Katar Hol) vs E-2's Wonder Woman, Green Lantern vs. Green Lantern, Superman vs. Superman (being the first known meeting of the two Supermen, as they didn't know about a previous one), and Green Arrow vs. Black Canary. The JLAers all win eventually (with the Supermen fighting to a draw), but Black Canary is nearly killed by an energy blast from Aquarius (but Larry Lance takes it instead, dying). The teams bury Larry, and then unite to defeat Aquarius. Black Canary feels drained by the death of her husband, and asks the Earth-1 Superman to take her to his Earth, where she plans on joining the Justice League of America.
This issue marks the first Silver Age appearance of the Golden Age Superman (who has yet to be depicted as much different than his Earth-1 counterpart).
Peril Of The Paired Planets
Meanwhile, aliens capture the Red Tornado, and the Creator Squared plans on using him to draw Earth-1 and Earth-2 together to destroy them. These aliens defeat the Earth-2 Superman and Dr. Mid-Nite (striking down the Earth-1 Superman and Batman, with Batman/Dr. Mid-Nite likely being linked from their battle with Aquarius). They then take out Flash (Jay Garrick) which causes Flash (Barry Allen) to fall. Both teams call in all members (with the JSA including the Earth-2 Batman and the Spectre) as the Earths begin to merge. On Earth-1 aboard the JLA Satellite, Black Canary, who came from Earth-2, figures she is the cause of the problem, as she came from Earth-2.
Where Valor Fails -- Will Magic Triumph?
While the Earths are merging, the aliens stop all of the JSA members except for Dr. Fate, Johnny Thunder and his Thunderbolt (which takes out most of the JLA, except for Green Arrow and Black Canary). Fate, Johnny and the T-Bolt go to crypt to free the Spectre (perhaps he sent them a ghostly apparition in the previous issue so they knew how to find him, as Spectre had been busy in his own 10 issue series before this). The Spectre prevents the Earths from colliding (at the temporary cost of his own cohesion), while Dr. Fate and the Thunderbolt defeat Creator Squared. The menace averted, the teams revive, with Green Arrow to wonder about the return of the Spectre (who does come back later, on Earth-1 in the pages of Adventure Comics).
This eighth JLA/JSA adventure sees the first appearance of the Earth-2 Batman (briefly, other than an imaginary story) as well as the what happened to the Spectre after his own series.
Building upon the previous batch of stories, even more adventures were in store for the JLA and JSA!