Uncanny X-Men: The Complete Collection by Matt Fraction #3

Plot

As Cyclops struggles to create a safe haven for mutants on Utopia, Magneto suddenly arrives -offering to join the X-Men! And to prove his good intentions, the Master of Magnetism undertakes a painful feat that might save another lost X-Man's life - or might just kill him. Then, after the events of 'Second Coming,' the mutant race has Hope again - literally! Witness the stunning emergence of a new generation of heroes! Plus: Things between Kitty Pryde, Emma Frost and Sebastian Shaw come to a head! And why are the X-Men all getting sick at once? The Sublime are back, and they've unleashed a contagion on Utopia. Can the mutants fight a microscopic foe, or will this be their final battleground? Matt Fraction's blockbuster X-Men run concludes!

Collecting UNCANNY X-MEN (1963) #520-522 and #526-534, and UNCANNY X-MEN: THE HEROIC AGE #1.