From Yen Press:
Sora, a young boy who lives a peaceful life on his tropical island home, is set adrift when a horrible storm wrecks the world he loves and separates him from his friends, Riku and Kairi. In another world, the Disney castle is in chaos when King Mickey goes missing, and it’s up to Donald, the court magician, and Goofy, the captain of the army, to find their king. When both Sora and the King’s allies happen upon each other and learn that the ills that have befallen their worlds are the doing of dark beings without hearts known as the Heartless, the three recent acquaintances take up arms together in an epic quest to travel to unknown worlds, set those worlds right, and find their friends!!