In space, Corsair is fleeing towards Earth, bringing with him a protracted four-issue story arc involving Lilandra and the Shi'ar and the Starjammers and the Imperial Guard and Deathbird (now seen in these pages for the first time, having debuted in Ms. Marvel #10 in October 1977). We also have the Brood, who display none of their later Alien-like traits, instead acting mostly as thinking minions of Deathbird, who of course, eventually turn on her.
Characterwise, the most important bit in this is Corsair revealing himself as Cyclops father. This makes the timeline rather wacky. Corsair has been gone for 20 years, it keeps repeating. And Scott was ten, wasn't he? So Cyclops is 30, now? That can't be right, can it? Corsair keeps referring to his wife as "Anne" for several issues before realising his mistake (she'd already been named "Katherine") and calling her "Katherine Ann".
#157 teases the return of Phoenix on the cover, which is way sooner than I'd expected. Turns out to be Kitty dressed up in costume. This is a good moment for her (as is the bit where she phases into space), and she's rapidly becoming actually competent. She's 14 now, we're told in the next issue, and Peter is 18. And so far there's no actual indication that he's acting on any attraction that may or exist, so this is staying firmly off the Chart. The age of consent in New York is 17, by the way. I do not know what it is in Shi'ar space, but I would guess that the Starjammer counts as a U.S.-flagged vessel.
We end up with Lilandra restored to that throne, but Professor X in a coma. Oh dear...