("And this is how the band got together.")
Wow, that was fast. The X-Men's ion-trail isn't even cold, and Xavier has given them up for dead, and started recruiting their replacements. Way to go, Charlie. I wouldn't be able to replace my dog that quick.
Speaking of dogs, we start off in Scotland with Moira MacTaggert. She's surprised by the arrival of a wolf (what? What did you think I meant?), which would be strange enough in the 20th century even before you factor in that the lupine in question appears to be ginger. Before Moira's astonished eyes, the wolf transforms into a fourteen year old girl, Rahne Sinclair, whom Moira personally delivered, Scotland hospitals being renowned for being so short on obstetric staff that they frequently outsource to world-renowned geneticists and/or the daughters of local lords. A crack team of Bible-bashing torch wielders arrive to deliver God's justice (i.e. kill a child), but Moira scares them off. That done, she resolves to bring her new wolf cub to Charles Xavier, to see if he can
Meanwhile, in Brazil, Roberto DaCosta is playing in a football match, watched by his girlfriend as his father. It would appear Roberto is the star player, but his opponents are far from happy about playing against someone half-black, and resolve to beat the crap out of him until he's pretty much black all over. Which they manage, I guess, though probably not in the way they were hoping for.
Unsurprisingly, this exceptionally public mutant-outing leads to full-scale panic.
Deep in the Kentucky Appalachians, we meet sixteen year old Samuel Guthrie, who has given up his awaiting college scholarship to replace his dead father in the local coal mine. Unsurprisingly, the same kind of miner owners that will work a man until he dies of black-lung are also the kind who'll let the support struts get too weak, and there's a cave-in on Sam's first day. Fortunately, the stress activates his latent mutant abilities, and he's able to blast himself and a trapped colleague out to freedom by somehow turning his feet into rockets.
Next on our whistle-stop tour: the Medicine Bow Mountains, just outside Sundance, Colorado. A young Native American girl sits in tune with nature (to the point where she can commune with cougars), only to learn from her wise and kindly grandfather Black Eagle, whose also a shaman - because in the Marvel Universe every single goddamn Native American has a wise and kindly paternal figure who's also a shaman - that he's sending her to Charles Xavier. She has "powers of the mind" that Black Eagle wants her to learn to use under tutelage (for those who don't already know, Dani can create illusions of a person's worst fears). Our girl Danielle Moonstar is appalled, disgusted that her blood could sell her out to the white man, the enemy of her blood - because in the Marvel Universe every single goddamn Native American also has a hatred of the white man that then becomes a wary trust and finally a strong enough bond of friendship for the phrase "I now realise that you are my tribe" to be uttered (unless they get themselves killed first, like Thunderbird). Black Eagle tries to calm Dani down by telling her that Xavier was her father's closest friend.
(So how come Professor X never mentions the guy, huh? Because he's too busy making friends with more white people, that's why. Hell, the guy was so furious that Cyclops left and the team chose a black woman to replace him as leader that Charles got himself infected with an alien's egg just to escape the shame.)
All of this is being observed by Pierce, a man apparently so lethally dangerous he can get away with wearing an 18th century wig along with a pink coat, and who is apparently determined to kill Xavier and the new mutants which are now manifesting. A woman named Tessa tries to talk him out of his plan, but she's apparently stuck in a recycling bin (or maybe three small toploader washing machines), so there's not much she can do. Pierce dreams of booting the mutants out of the Hellfire Club, and apparently this is stage one of the plan. That night, vicious goons in high-tech armour (presumably on Pierce's orders, though I fail to see why) beat Black Eagle to death, causing Dani to swear vengeance.
Xavier himself has other business right now. Moira has arrived with Rahne, and Reed Richards has sent over Xi'an Coy Mahn The latter is capable of possessing the minds of others (as she demonstrates on Moira, which doesn't go down well at all with the werewolf), and is one of the "boat people", a refugee from Vietnam. Admittedly, that's only a small nod toward the idea that developing an international character requires more than simply saying "I am from that place, which is not this place" over and over and over again (see Colossus, Nightcrawler, Storm, etc.) , but at this point I'll take it. Combined with Rahne's deeply held Christian convictions (which tragically have led her to conclude mutant powers are "gifts from Satan") and Roberto's mixed-raced heritage, there's some evidence of Claremont growing as a writer, even if I'm not sure Roberto's race ever comes up again. 
Xi'an and Rahne want to be tutored, Xi'an for fear she becomes like her villainous uncle, and Rahne because - well, I'm not sure, but I suppose even a gift from Satan is better studied than ignored. Xavier is hesitant, not particularly enamoured with the idea of teaching another group of youngsters about how best to go about getting themselves massacred, but Moira turns him around by reminding him his true dream is to help mutants learn to live with themselves - beating the crap out of supervillains was something of a sideline.
(Hands up who buys that, by the way. If alcoholism is truly a disease of the mind, and if madness is doing the same thing time after time and expecting a different result, then Moira is being the mother of all enablers, right here. Hell, these poor freaks don't even make it to the end of this comic before they're trying to avoid a brutal death at the hands of their enemies, though in fairness they both began their trips to America that way, too).
After some low-level haggling, the deal is done, and Xavier's is born anew. Moments later, Black Eagle's letter arrives, asking Charles to help out his granddaughter. Rahne and Xi'an have been students at the institute for exactly one page, and already they're off on a field trip. What could possibly go wrong?
Xavier, Moira and the two teenagers arrive in Colorado the next day to find Black Eagle is dead, and that Dani is on the run from a trio of pink-armoured Hellflunkies on jetbikes. Xi'an saves her from her pursuers (too late to help Dani's cougar, alas, but that's what you get for taking a wild big cat and domesticating it to the point it turns, ahem, pussy), and Xavier interrogates the only one she left conscious. It turns out Pierce, whoever his, isn't just looking to move up with Hellfire. He's looking at total mutant extermination, and the next two kids on the death list are Guthrie and Da Costa. There isn't time to save them consecutively, so Xavier splits the team in two. Once again, this is immediately putting in danger three teenage girls who you've only just been persuaded that you could avoid getting killed.
Moira, Xi'an and Dani head for Brazil, By the next day they've picked up Roberto's trail, which leads to them quickly being arrested for the crime of asking about Da Costa just before someone tried to have him abducted, and after his girlfriend disappeared. Nice to know the Brazilian police have the matter well in hand. Using her powers, Xi'an and Dani escape, leaving Moira to explain what's going on, and they track Roberto down using a portable Cerebro scanner. They follow him to the Rio slums, and watch him meet up with three Hellfire mooks. It was they who kidnapped Juliana, his girlfriend, in order to bring him to heel. Roberto powers up and tries to fight his way out, but his abilities keep shorting out on him. Even with Xi'an and Dani joining the fight, the three assailants (who, we learn, are the mercenaries Wolverine carved up in UXM #133, and who showed up again in UXM #152) manage to kill Juliana before they're defeated. Roberto is apoplectic with rage, and tells his rescuers that he has no intention of letting some random American "teach" him, though he's happy to join Dani's quest for vengeance and blood.
We switch focus to Xavier and Rahne. Moira has called to let them know she's escaped the Brazilian justice system, but that there's already been one child killed in all this mess. Xavier is still pondering the ramifications of this when their jeep is knocked off the road by a flame-sheathed human cannonball. Pierce has recruited Guthrie! I've always loved that twist, rather simplistic as it might seem by today's standards (then again, it might not - depends how much Geoff Johns you've been reading). Charles is knocked unconscious and takn prisoner, but Rahne instinctively transforms into a wolf, and thus drops off the sensor readings of the men accompanying Guthrie - now codenamed Cannonball. They take off in their helicopter, but Rahne is able to follow Xavier's scent back to base, transforming to and from wolf, human, and whatever it is lies between, whenever necessary, meaning she's already a more impressive example of lycanthropic derring-do than Altered Beast managed.
|"Walk along, kick; walk along, kick; walk along, kick.|
What an experience." - Dominic Diamond
Rahne makes it through the Hellfire installation's outer defenses, and perches on the roof to peer in through a skylight. Xavier has been hooked up to a combination power-dampener and brain-raper, with the Tessa woman from page 13 next in line for a nasty bit of synaptic scrambling. Cannonball arrives to put an end to her snooping, but Roberto, Dani and Xi'an have shown up too, and after a brief fight, they break into the base.
Once inside, however, things go far less well. Pierce is a cyborg, just like some of his men, and neither Dani nor Xi'an can use their powers against him. Both are easily dealt with, and Rahne receives a punctured lung when she tries to take on Pierce hand-to-hand. Roberto doesn't do much better, hit by Cannonball from behind and shaken out of his alternate form.
In the end, though, it's Cannonball who saves them (and whilst putting him on Pierce's side initially was a nice idea, having him save the day at the last minute must have been horrifically cliched even in 1982). Pierce has forgotten an elementary rule of supervillainy: find out a prospective employee's feelings regarding cold-blooded murder before you hire them for your security detail.
Pierce responds by attempting to put a bullet through Sam's skull, but the brief distraction is all Rahne needed to turn off the machinery keeping Xavier helpless, and Pierce is soon zombified by the force of Charles' will. There's some brief concern over how to keep Pierce (currently under Karma's control) from breaking free and killing them all, but the now-free Tessa promises to take him to her Hellfire masters, who are liable to look rather poorly on attempts to have them all killed. Sam is somewhat confused as to what to do next, but Roberto (who has decided to let Pierce live so as to not be like him, whcih makes precisely zero sense) makes things abundantly clear: Cannonball has made his bed, now he can lie in it, and count himself lucky his isn't bleeding brain matter into the pillows.
A fortnight later, Xavier calls his class into session. His charges have changed into their New Mutant uniforms (not dissimilar to the second set of costumes worn by the original X-Men), though Dani has made a few Cheyenne-centric changes to hers. Professor X decides to let it slide, telling himself he would be wrong to force her to conform, which is an interesting position, I think. Could Rahne get away with wearing tartan? What if Roberto decided he wanted a neckline in the shape of the Sugarloaf Mountains. Hell, what if Kentucky-born Sam (who arrives a few minutes later, having been given a second chance by Xavier) decides he wants a medallion displaying the Blood-Stained Banner? 
I'm just saying, it would be interesting to know just how far Xavier would allow this customisation of his uniforms to go. Though of course Dani's boots are awesome, so there may be some aesthetic considerations at play as well.
In any case, the New Mutants are now officially a team. Their first adventure together was published until five months later, however, so it'll be a while before we see them again. We still have to work out way through the X-Men's adventures in space. Also, Dazzler might get a sore throat, or something, and we don't want to miss that now, do we?
The main question to consider here is how long it's been since the X-Men and Lilandra headed into space. At least eight days pass between Moira meeting Rahne and the first time we see Xavier in these pages, but that alone strikes me as far too short a time for Xavier to have given up searching for the X-Men (even if the Shi'ar wouldn't return his calls, I'm sure the Fantastic Four would happily do some digging for him).
Let's asume then that by the time Xavier heads off to see Dani Moonstar, a full month has passed since the X-Men's disappearance.
The story itself takes place over three and a half weeks.
Tuesday 17th of May to Sunday 12th of June, 1983.
Lebanon, Israel and the United States sign an agreement on an Israeli withdrawal from Lebanon.
The UK Conservative Party under Margaret Thatcher win re-election in a landslide.
"<What can we do?! We're only fourteen! They are -- monsters!>"
"<So am I.>" - Juliana and Roberto.
 Not that I'm arguing having Sunspot constantly wandering saying "As a person of mixed race, I think the following..." would have been a good idea. I'm just saying it was something to his heritage beyond being from Brazil, and so if it isn't used, and nothing else is brought in on top of it, you reduce Da Costa to the previous model of Claremont's non-American characters: occasionally saying things in a foreign language that are immediately translated into English.
 Yes, yes, I know, Kentucky were never officially part of the Confederated States of America. Enough of them joined up with Davis' forces to get them their own star on the Confederate Battle Flag, though.