Continuing the youthful, 21st-century reimagining of Marvel's iconic quartet! Threshold, Fountain, Magnificent Brute and Dreamcatcher. These incredible entities hold the key to a cosmic conflict that has raged for untold millennia - and which now embroils the Fantastic Four! Then, the FF are pulled into a madman's scheme when those closest to them are drawn back through time. What awaits them in the year 1483 is a man with a quest to transform the world: the alchemist supreme, Ultimate Diablo! Reed Richards' attempts to create a Cosmic Cube pierces the barriers of a hundred universes, and falling through the opening into our unsuspecting reality is the keeper of the Power Cosmic - the Ultimate Silver Surfer! Plus, the Mole Man, Thanos, Agatha Harkness and the Salem's Seven! But when a group of X-Men from the future come back in time, why do they want to assassinate the FF?! And when the cataclysmic events of Ultimatum rock the entire Ultimate Universe, what will become of the Fantastic Four?! Collecting ULTIMATE FANTASTIC FOUR (2003) #33-60 and ANNUAL (2005) #2, ULTIMATE X-MEN/FANTASTIC FOUR (2005) #1, ULTIMATE FANTASTIC FOUR/X-MEN (2006) #1, ULTIMATE X-MEN/ULTIMATE FANTASTIC FOUR ANNUAL (2008) #1, ULTIMATE FANTASTIC FOUR/ULTIMATE X-MEN ANNUAL (2008) #1 and ULTIMATUM: FANTASTIC FOUR REQUIEM (2009).