The first, is where the two teams are attacked by people who had long passed away, the second was dealing with the return of an old foe and a mystery, and the third, an extra long team-up, had the two teams dealing with the New Gods (and was history for both a sad and happy reason as well.
Time to look back at a few meetings of the Justice League and Justice Society....
Crisis From Yesterday
Before getting to the battle, a chance to review with the JLA and JSA, as they took the time...Earth-1 Batman reflects on his meeting with the Earth-2 Huntress in Batman Family, Earth-2 Flash says his life is supposedly easier after revealing his identity to the world in DC Special Series #11 (or so he says to Earth-1 Flash), Earth-2 Green Lantern was starting a back up in Earth-1 Green Lantern's title, and the JSA had just ended their All-Star Comics run with issue #74.....
Jonah Hex, Viking Prince, Miss Liberty, the Black Pirate and the Enemy Ace! These past heroes were plucked out of time by the Lord of Time (himself tired of battle from manipulations he had with Kamandi and Karate Kid), had retreated to a place "out of time" where he had constructed the Eternity Brain, a machine that would help him take whatever he wanted...by stopping time!
The JLA and JSA members at the party were all rendered comatose, except for JLA members (Superman, Flash, Elongated Man and Hawkman), and JSA members (Dr. Mid-Nite, Wonder Woman, Star-Spangled Kid and Huntress). They remaining members faced History's Heroes again, and lost...giving the Lord of Time hope they now had the fight in them to defeat the Eternity Brain....
Crisis From Tomorrow
The JLA/JSA were using a modified Cosmic Treadmill to go to where the Lord of Time was, his castle outside of time...all as History's Heroes were attacking the Lord of Time's castle as well, but finding out it was well defended by the Eternity Brain. Meanwhile, back in 1978, Aquaman (who had been late to the party due to being on monitor duty), was working to revive the comatose heroes.
Back at the hospital, as after clearing all the heroes of the energy leaving them comatose, Green Lantern was able to follow the trail through time and rescue the others. After returning History's Heroes to their proper times, the JLA and JSA would recover...even Elongated Man was able to bounce back from his injuries!
Ending on a happy note, the JSA now had to move to being a back up in Adventure Comics (and they were dealing with a sinister plot by the Secret Society of Super-Villains, who were taking on less active members of the team....).
The Murderer Among Us: Crisis Above Earth-One
This time, there was a murder among the team while gathered in the JLA Satellite....that of Mr. Terrific, who had wanted to be a part of this gathering, as he told the two Flashes, because of the return of an old enemy of his (and the Earth-2 Flash)...
Zatanna tried to trace the identity of the killer off a piece of metal, but a mystic backlash...putting her in a coma, leaving the rest of the present members of the two teams to wonder which of them was the killer!
....that someone on the JLA Satellite must be the killer!
So, Superman had the Green Lanterns and Dr. Fate put a mystic green energy shell around the Satellite so no one could leave...and set the detectives Earth-1 Batman and Earth-2 Huntress into finding out which teammate could have done it.
With Batman going through the clues, and Huntress checking a hunch to see what the Spirit King was stealing in Gateway City using the Transmatter Machine to link to the JSA's Brownstone computers...
...Batman was able to deduce the identity of the killer!
Scroll quickly if you don't want it spoiled!
The JLA tries to claim victory even with the villain escaping (as they didn't believe any of the heroes were responsible), but the JSA somberly left the JLA Satellite to go to Earth-2 to bury Mr. Terrific (and, later chronicled in a flashback, finally catch the Spirit King, freeing Jay Garrick Flash from his clutches, in Spectre #54 of the 1990s), and had their last adventure in Adventure Comics in the 1970s.
Where Have All The New Gods Gone?
The first four of each team were hijacked....and appeared in New Genesis!
JLAer Superman explained where they were (having met the Forever People and been to Supertown once in the days of Superman's Pal, Jimmy Olsen), that this was the home of the New Gods...
....a race of incredibly powerful beings who were forever at war with their opposing numbers from Apokolips.
Firestorm....had wandered off into the empty Supertown...finding Orion, and knocking himself unconscious through the shock. As Orion was tending to Firestorm, the rest of the teams arrived, and fought Orion, at least until Metron, Mr. Miracle, Big Barda and Oberon arrived via Boom Tube.
Knowing Mr. Miracle, Superman got the team to listen to him, who explained that Orion was moody due to feeling responsible for this tragedy, as he had recently killed Darkseid, which must have triggered this attack by Apokolips to empty New Genesis, that had been done by members of the Injustice Society (Fiddler, Icicle and the Shade).
The heroes would go to Apokolips and split into teams (coordinated by Metron, who had pulled the JLA/JSA from their Transmatter Machine to New Genesis), to find out where everyone had went.
On a sad note, this was the last issue completed by artist Dick Dillin, who passed away while working on the next issue. His incredible legacy for all he did for the JLA will always be cherished.
with a great deal for the heroes to do all over Darkseid's home planet of Apokolips!
An incredible welcome for new artist George Perez, who was also working on New Teen Titans at the time, even though Dick Dillin had completed about six pages of the issue before he passed, DC had Perez draw this entire issue; the issue also had a few of Dillin's co-workers tell of that artist's great contributions to comics, as well as of his gentlemanly nature, in the letter's page).
...which was that Darkseid, after being revived by the Injustice Society of the World members of Fiddler, Icicle and the Shade, had planned to have Apokolips "transferred" in time and space...
...and have it take the place of Earth-2, which would destroy that world and give Darkseid a universe of his own to plunder!
The heroes had plenty to do to stop him!
Thankfully, Metron used all this distraction to redirect the Re-Creation Machine, having it focused now on Darkseid....which undid his return, defeating him and leaving the members of New Genesis free to go and rebuild their home.
Volume 3 and Earth-S was in Volume 4), but one more collected volume was to come!