They backtrace the call to Chile, visit, and get involved in a plot regarding the Savage Land Mutates and Zaladane, a villain first introduced in Astonishing Tales #3. She claims, on the basis of her name, that she is the sister of Lorna Dane.
#250 uses the word "katabatic". That's a good word. I like it. Shame about the rest of the issue, which consists of an old-school team-up between the X-Men and Kazar to kick Zaladane's ass and save Lorna. This series has completely lost its way now, which is possibly meant as a kind of metaphor because so have the X-Men, but still.