The kids are visiting a carnival, where the motorcyclist stunt act Team America are performing. These were introduced a year ago in Captain America #269, and had then gone on to star in their own ongoing Team America series. These were the distant days when you could promote a line of toys by getting them in a comic book, and that's what's gone on here - someone has tried to relaunch an Evil Knievel line with different names after the assault charges. It is therefore hilarious that on page 20 Sunspot punches Wolf for giving him some lip.
So. Silver Samurai and Viper are at the carnival too - tracking an unspecified group. The New Mutants, perhaps? Nope - they're after Team America. There's a fight, Dani becomes the "Dark Rider" and protects Team America and wakes up amnesiac and captured. The others regroup: Xavier theorises that the Dark Rider is a gestalt formed by the members of Team America, who are mutants (see, relevant!). They are blackmailed into conducting a thieving expedition, and go ahead, with Xavier monitoring them.
That leaves the New Mutants free and unsupervised, and they pay Xi'an's uncle (now the Kingpin of San Francisco, if not in name) a visit looking for intel. This would be Nguyen Ngoc Coy. Another digression about nomenclature: the Vietnamese names here are broken, even worse than the Russian names. Nguyễn is a family name, not a personal name. As is Tran (her brother's name). Leong exists in Vietnamese as Lương, but is another family name. Looks like someone didn't get the memo about East Asian names often being FamilyName PersonalName, then.
I seem to recall I was writing about a comic. Oh, yes. So, Nyugen spills the beans, and the New Mutants liberate Dani. Meanwhile, Team America thieve that macguffin. Both teams are successful, although Xavier is pissed off that the New Mutants went on a field trip without his permission. But this is at a hideous cost. Karma has promised herself for a year's service to her uncle. That thing, that she was so determined to avoid in Marvel Team-Up #100, she's willingly signed up for in order to save Dani. Hardcore.
And then suddenly there's an explosion! Oh noes!