The Destiny Islands are a beautiful paradise where children's laughter abounds. Day after day, Sora, Riku, and Kairi talk and dream of new places, new worlds beyond their islands. They ponder the usual questions that adolescents do--about the world outside, about their own existance. Little do they know a great destiny awaits them. One stormy night, a terrible darkness invades the Destiny Islands, and the three friends are seperated.

Meanwhile, Donald and Goofy discover that their King Mickey has suddenly left the palace. He left a note asking Donald and Goofy to find a key, a key to their survival. Goofy notices that stars are starting to go out. Every time a star goes out a world is gone, consumed by darkness. But who could be doing this?

Sora awakens in another place, not his Island but a town. And he wields a real sword, shaped like a key. And as he trys to figure out why he's here, dark creatures emerge from the ground and attack him, there seem to be endless amounts of them. These are the Heartless and they will never stop hunting the wielder of the Keyblade.

Donald and Goofy are also in Traverse Town in search of the key, and are forced to fend off the Heartless. In an unexpected encounter, the heroes paths collide. Thus does their journey begin...

(Story based on Kingdom Hearts Instruction Booklet)