Cerebro has been stolen - and the trail points directly at the government's premier think tank, the Baxter Building! The X-Men aren't happy about it - and the Baxter Building's most famous residents, the Fantastic Four, aren't happy about an angry team of mutants showing up on their doorstep! It's FF versus X-Men in an all-star blowout as Ultimate Fantastic Four's Mike Carey is joined by superstar artist Pasqual Ferry for this tour de force of Ultimate action! Plus: in-depth bios on the Ultimate X-Men, the Ultimate Fantastic Four, the Ultimates and Ultimate Spider-Man! Collects Ultimate X-Men/Fantastic Four Special, Ultimate Fantastic Four/X-Men Special and Official Handbook of the Ultimate Marvel Universe 2005 #1 and 2.