Donald and Goofy arrive in Traverse Town, a haven for those whose worlds were already destroyed. They notice a star- that of Destiny Islands- fading away, and decide to look for the one with the key and Leon.
Unknown to them, King Mickey's dog Pluto has already found Sora, who wakes up and, after initially assuming that it was all a dream, realizes that he is in a different world. Following Pluto, Sora meets up with a shopkeeper named Cid, who explains to him about Traverse Town. However, Sora is determined to find Riku and Kairi, and sets off in search.
While exploring, Sora soon encounters The Heartless all around town in every nook and cranny, and eventually stumbles upon Leon- Squall Leonhart, to be specific. Leon warns him that the Heartless will continue to harass Sora as long as he has the Keyblade, and battles him for the weapon. The fight ends with Sora passed out as Leon's friend Yuffie arrives, while Donald and Goofy run into Aerith.
Meanwhile, at a different world, Riku awakens on a stone platform. He calls out to Sora and Kairi, unaware that he is being watched...
At a hotel, Sora learns about the Heartless from Leon and Yuffie, with Donald and Goofy doing the same from Aerith. As they explain, a researcher named Ansem studied the Heartless and compiled his research in a report which was scattered throughout the worlds. Just then, the Heartless attack, forcing them to flee; before leaving, Leon tells Sora to find the Heartless' leader.
Eventually, Sora arrives at the Third District, as do Donald and Goofy. A group of Heartless then blow Donald and Goofy off a balcony and onto Sora, who they realize has "the key." But there is no time to introduce themselves as more Heartless appear, accompanied by their leader, the Guard Armor.
The fight with the Guard Armor is no easy feat, but the three vanquish their enemy. From there, Sora learns that Donald and Goofy have been looking for him, and are searching for their king. While Sora is reluctant to join them, Leon tells him that they may be his best chance at finding his friends. And so, the three join forces as companions in a long adventure.
- Goofy: All for one, and one for all!
Meanwhile, a group of villains keep note of Sora and friends, realizing that they are out to save the worlds. Their leader, Maleficent, reminds them that Sora has recently obtained the Keyblade, and that his fate is up to the universe to decide...