Collects X-Men/Fantastic Four #1-5.The X-Men and the Fantastic Four team up with the help of Pat Lee and Dreamwave Studios in this heart-pounding adventure! Can the two teams put their differences aside to stop a creeping menace from outer space that threatens our planets very existence? Even as the heroes trek into the stars, the real threat to their mission might just be among themselves! Its the X-Men and Fantastic Four versus...the X-Men and Fantastic Four?! An unexpected adversary turns Marvels two greatest hero families against one another.