As many stories contain, Sora has a long lost sister. But this story, is the true story behind his sister. She is the one who named the Heartless, invented the Gummi Ship, (With help of her friend) and the one who discovers all the different worlds. Why? Just because of the Heartless attacking her world...She got separated from Sora and she is desperate to find him. With the help of her three companions, they all travel the worlds together to find him. But will they ever find him? Or will they fail?