Hope was the first mutant born after the events of Decimation. She was born in Cooperstown, Alaska to Louise Spalding and an unknown man, with Cerebro blowing up the moment little baby Hope was born. Cooperstown was attacked by the Purifiers soon after, who had been warned of the baby's birth by the time-traveling sentinel known only as Nimrod. Hope was the only child left unharmed after the Purifiers attacked and was eventually saved by Cable. Cable claimed that the baby, Hope, was the messiah and was destined to save all mutants and all of humankind alike. However, there were those, such as Bishop and the Purifiers, who believed that the birth of Hope was the end, that she was a sort of "Antichrist," who was destined to kill a million humans in six minutes. This would be responsible for turning humanity against mutants once again, and creating a new era of mutant persecution (which would one day turn out to be the timeline in which Bishop was born).
Soon after, the Marauders kidnapped the baby, and she was delivered to Mister Sinister (who turned out to be Mystique in disguise). Mystique made the baby touch the comatose Rogue. Having believed that she had just killed her, Gambit took the baby away from Mystique, but to his wonder the baby was fine, and Rogue was cured. After a battle between the Marauders, X-Men, and Predator X, Cyclops comes to the decision that the baby would be safest with Cable, and so Cable takes the baby Hope to the future. However, Hope and Cable are tracked by Bishop, who still means to kill Hope in an attempt to prevent the creation of his future.
The first mutant born after M-Day, Hope Summers is believed to either be the mutant messiah or the harbinger of death for humanity. She is an Omega-level power mimic, and possesses a connection to the Phoenix Force.