The story behind Kingdom Hearts is that Sora, a 14-year-old boy whose world is shattered when a violent storm hits his island-paradise home, and he is separated from his two closest friends, Riku, a 15-year-old boy, and Kairi, a 14-year-old girl. The storm scatters the three to different and unknown worlds. Sora, while searching for his friends in a strange and mysterious land, meets Court Wizard Donald and Captain Goofy, protectors of the Disney Castle, who are on a mission to find King Mickey.

The three learn of threatening creatures known as the Heartless - beings without hearts derived from an unknown dimension and, as it turns out, the ones responsible for the devastating storm. And while the Heartless invade and destroy many worlds, the Disney villains collaborate behind the scenes to realize their devious intentions. Upon discovering the link between the Heartless, the storm and the disappearance of the King, Sora, Donald and Goofy join forces to recover Sora's friends, return the King to his rightful position and save the universe from the Heartless.