Days of Future Past
Of all the world's possible futures, one was so grim that the mutants who hadn't been exterminated by the robotic Sentinels were herded into concentration camps. X-Man Kitty Pryde, one of the few survivors, set out to change all that - by sending her mind back to the present day! As her friends were slaughtered in the future, she fought side-by-side with today's X-Men to make sure that that future would never come to pass!