It then takes a couple of panels to helpfully clarify the relationship between Mesmero and Magneto. Magneto somehow knows about the robot Magneto tag-teaming with Mesmero and claiming to be Lorna's father (We never did find out who built that and why, did we? We'll see if some later writer picks that up.)
Magneto then explains what he was doing there - he had left Muir Island (it gets a name, finally!) and tried to attack the X-Men at the mansion but found it empty, only to find Beast calling, who he then trailed to Texas. During this description, Claremont's captions finally make the transition from narration to full-blown prose. I quote:
"Why?" Cyclops asks, after Wolverine reluctantly sheathes his claws.
"Why us, Magneto? Why now?"
Nightcrawler 'ports out and finds out that the wagon is quite high up, and barely survives the experience. They then realise they'd better not kill Magneto yet. Except: the team here contains Storm, Banshee and Phoenix, who can all fly, Colossus, who we have already seen can easily survive a terminal velocity landing. That leaves Wolverine (who is not yet being written with super-healing as a power, admittedly), Cyclops, Nightcrawler (who can teleport) and Beast. Surely getting everyone down safely should not present a problem.
So, once they get to Magneto's secret Antarctic subvolcanic city-sized base (seriously, it's 5 square miles, and it's just him this time as far as I can tell), then they attack him. Ineffectually, despite having had time to prepare telepathically, and despite their encounter with him in #104 which should have had them training specifically for this. And they've got Phoenix with them, too! Magneto has decided to take revenge on them for turning him into a baby (even though really that was Xavier and the X-Men didn't know a thing about it), and places them in a custom prison, where their motor controls are regressed to those of a 6 month old...
Magneto then goes on a spree attacking research installations in Australia and New Zealand, and in particular Woomera. We're given handwavy excuses for why the Fantastic Four, Champions and Avengers are unavailable to stop Magneto, which is important in establishing the feel of a larger Marvel universe. If the X-Men were free, we could accept them turning up first to deal with Magneto, but it needs to be shown that nobody is around to stop him.
In this era they were quite good at giving footnotes for other storylines (indeed, Magneto's attack on Cape Citadel way back in issue #1 was mentioned), but these go unannotated. Do these refer to particular contemporary stories? X-Men #113 was released in September 1978. Gentlemen of Leisure have the Avengers being "under virtual house arrest" being a reference to Avengers #181, which is a bit weak, not only because it was released in March 1979, but also Beast was part of the Avengers line-up there. The identification of the Fantastic Four breakup with Fantastic Four #191 seems plausible enough, though.
Xavier and Lilandra are on holiday in Kirinos in the Cyclades in Greece (and we discover in a narration that Moira had dumped him, back in the day). It appears to have escaped the Internet's attention that although this is a real island group, Kirinos is fictional. Claremont will use it again. He's upset that his "telepathic rapport" has been broken, but apparently not enough to turn on the television, where he would learn of Magneto's reign of terror. Magneto feels stronger than ever since his reversion to adulthood, and has managed to get up to his asteroid base (last seen in X-Men #5), which is now given a name - Asteroid M. (Magneto likes naming things M, doesn't he? Just like Xavier seems to like naming things X. He also has a big 'M' flag).
We discover that Storm has such l33t th33f sk1llz that she can pick her way out of a lock even though she's regressed to babyhood. She's just that good. She then frees the rest of the X-Men, and they work out a plan for ambushing Magneto when he arrives. They then defeat him with teamwork! There's a moral lesson there somewhere. Unfortunately, in the battle the system that keeps the lava out has been damaged. Magneto makes a hasty exit. Jean flies after him (with Hank as a passenger), but only makes it as far as the Antarctic surface before passing out. Phoenix is immensely powerful, but only in short bursts - she burns out. The other X-Men are still trapped below...
X-Men has gone monthly now, for the first time since it was cancelled, which is just as well given this tendency towards serialisation.