Last arc, Magneto betrayed his students and burned the X-mansion to the ground. Homeless, they decide to go hook up with X-Factor (who have their own living ship, stolen from Apocalypse). The ship takes them underwater, just for fun to cheer them up, and they meet Sub Mariner and fight a giant squid.
When Mr. No Fun Cyclops shows up, the ship explains to him that it was all for the sake of education.
It’s not a bad issue, but it feels like filler. We’re promised that next issue the story will deal with Ilyana now being a child again, but in the meantime, look at this picture:
There’s just way, way too many people in this book. The mutant world grows increasingly unwieldy. No wonder Scarlet Witch eventually kills them all with her “No More Mutants” magic after the turn of the century!