For months, the force of nature known only as Onslaught has struck from the shadows - but when the X-Men discover Onslaught's startling true identity, the villain's plan kicks into high gear! Determined to punish mankind for a litany of sins, Onslaught laid siege to the X-Men, Avengers, Fantastic Four and more - kicking off a cataclysmic conflict destined to deprive a world of its most revered icons!