*Dawnstar and Brainiac Five crash-land on a primitive planet with religious issues.
*Dev-Em, a descendant of Krypton who's been a very minor supporting character, inflitrates the Dark Circle on behest of some police organization.
*The missing five Legionnaires return home. Vi confronts Yera, declining to forgive her for impersonating her, but establishing an awkward peace - I guess - between them.
*Element Lad and Shvaughn have their smooching interrupted by a Legion mission to thwart some alien thieves in Hong Kong.
*Cosmic Boy takes a leave of absence. Shortly afterward, he and the other founders, Saturn Girl and Lightning Lad, formally tender their resignations to make way for new blood on the team.
*Timber Wolf agrees to undertake a dangerous and mysterious mission on his own as a bequest in Karate Kid's will.
*The team protects the three candidates for Earth's presidency from Khund assassins; Invisible Kid accidentally kills one of the attackers. Mojil Desai is elected the planet's new president.
*Element Lad is re-elected team leader.
*Prefiguring his late 80s/early 90s work on Justice League during its long "bwa-ha-ha" phase, Keith Giffen pencils and plots a Legion of Substitute Heroes special that plays the team as mostly ineffective and goofy, but they nevertheless save the planet Bismoll from the oh-so-1970s villain Pulsar Stargrave, somehow.
It's interesting to see just how little is happening during this period of the comic, but how incredibly entertaining it all is. There are fights and explosions and super-powered stuff, but the draws are the character interaction and the artwork. Steve Lightle's stuff is - and I know, I keep saying this - just so damn good.
I have to say, though, that while the proper book(s) are reliable and engaging and keep me caring about the characters, it's what Keith Giffen does with the Substitute Heroes Special that really warrants comment. This book is hilarious. It is actually a follow-up to an issue of DC Comics Presents from about two years previously. My copy has gone into hiding, but it had been a longtime favorite.
In that story, the then-new character of Ambush Bug had hopped on Superman's back just as he was traveling on some mission to the 50th Century. He stops in Metropolis in the 2980s, hoping the LSH could hold onto Bug for him, but they were out of town and he leaves him instead with the Subs. They are depicted as utterly incompetent, well-meaning goofballs, and they lose him. The book's a complete riot, and includes an amazing exchange between the Bug and the Subs' newest member, the unfortunate Infectious Lass. She is sent to distract Ambush Bug using her "feminine wiles," which works for about the half-second that makes up Bug's attention span. He, who has spent the entire escapade thinking he's at an amusement park, asks her what she does, having already been tickled by the Subs' various and ridiculous powers. "I make people sick," she says. "I'm sure you do, honey," he replies. I've loved Infectious Lass ever since.
In the special, the Subs and Gigi strike out for the planet Bismoll, where former LSHer Matter-Eater Lad has entered politics, and which has been invaded by Pulsar Stargrave - what a name! - and his disco fashion sense. Chlorophyll Kid has gained about a hundred pounds since we last saw him, and Infectious Lass has unwittingly passed along some gender reversal germs to Color Kid, and Matter-Eater Lad bites off Pulsar's nose. (It must've been the season for it; Ace Garp bit off Jago Kain's nose in 2000 AD around the same time.)
The book ends with Polar Boy coming to the sad realization that his team really is a band of incompetent boobs, and, in a final panel, realizes that their time has passed. In what would become a Giffen hallmark - this really does prefigure much of his work on Justice League a few years in the future - this could-be-touching epiphany is nothing more than a throwaway joke in the final panel.
The other really important moment is that the three founders all retire. While this has been telegraphed and hinted at for many months, it's still a surprising development. They'd been the core and the heart of things for so long that it would have been an inconceivable development just a couple of years before. Their story is far from over - in fact, there's a Legionnaires 3 miniseries about them that I don't own - and the books probably can't really exist without them, but it's a reminder that nothing's really all that safe in the 30th Century.