My overall reading experience with this book from the beginning has been: interesting at first, awful Magneto issue almost kills my interest entirely, okay that was interesting again, really enjoyed Dark Angel Saga, unsold but optimistic about upcoming Otherworld arc, issue 19.1.
This point one issue takes the story back to the Age of Apocalypse world that Jean Grey and Sabretooth have just returned to after a brief visit to the 616. It's clearly designed to set up the David Lapham AoA series, introducing a few new human characters (to me) and focusing on their last stand against Weapon X and his mutant army and their desperate final attempt to neutralize them before being wiped out. The almost unthinkable plan is: They have clone a number of experimental mindless clones of The Scarlet Witch and upon Jean's return use her to try and re-enact the "No more mutants" scene from House of M.
Magneto was real happy about that too, but he doesn't have too much time to worry about it. Because he and Rogue are killed shortly afterwards.
Part of the focus is on human William Stryker, or Prophet, and Miss Trask, daughter of Bolivar Trask, it seems likely they'll make the transition to the Lapham book with the surviving mutant cast, half of whom shown on the title/recap page are dead by the end of this issue.
This wasn't the strongest issue of UXF and it didn't quite make me sure to buy the new Lapham series, but I'll at least give it a look. I would rather they had gone right ahead with the Otherworld arc teased in issue 19 and included a preview of the Lapham AoA series.