Markus O. Sinclair is a 16-year-old living in the totalitarian society that is Vector City. As a soldier of N.O.R.A (No Obligations, Rules, or Authority), an insurgent group that seeks to overthrow the oligarchy that rules over the lives of the city's 48 million inhabitants with an iron fist, he does everything in his power to fight for the freedoms of his people. One fateful week, the world of Vector City is threatened by its gradual invasion by the Heartless. As his homeworld descends into further chaos, Markus awakens to the power of the keyblade. With his world consumed by darkness, Markus is thrust into a long and perilous journey to bring back his homeworld so that he along with the rest of N.O.R.A may work to finish what they started and liberate Vector City's inhabitants. Along the way, he will encounter many allies who will assist him on his quest to fight back the darkness, forging new bonds as well as saving many different worlds from sharing the same fate as his own.