The third and final act of the EPIC SONIC/MEGA MAN CROSSOVER EVENT begins here! 'Worlds Unite' Part Nine: Sigma has begun his conquest of ALL the worlds. Now it's up to Sonic, Mega Man and X to unify those worlds AGAINST Sigma! It's a 'who's who' of SEGA and Capcom heroes answering this important call to arms! But with Sigma still active on the unified world, he turns his gaze upon those left behind! Featuring the worlds of STREET FIGHTER, SKIES OF ARCADIA, NiGHTS INTO DREAMS, OKAMI, GHOSTS