The timeless nemesis of the X-Men, Apocalypse, has masterminded a new plan for ruling the Earth. This time it's not just one world he will dominate, but two. Apocalypse has opened a portal to the Capcom universe, a reality existing along side the Marvel universe, and has transported a group of powerful warriors known as Street Fighters in the Marvel universe. Apocalypse's intention is to pit these Street Fighters against the X-Men and eliminate them. With the X-Men out of the way he will use his new warriors to take over the Marvel universe, then the Capcom universe, leaving Apocalypse the despot of both worlds. However, Apocalypse has failed to consider that each Street Fighter plays and fights by their own rules. Apocalypse awaits as the titans of two universes clash: X-Men vs. Street Fighter!