- "I've been having these weird thoughts lately... like, is any of this for real, or not?"
The Kingdom Hearts series begins with a young boy named Sora having a strange dream. In a dark void surrounded by stained glass pillars, he is offered a choice to choose two of three weapons, one being the path he will walk, the other the path he will reject. After a series of trials, Sora is confronted by a mysterious black monster. Though he manages to fight it off, he is ultimately swallowed by it.
Sora awakens on his homeland, the Destiny Islands. Ever since a girl named Kairi arrived on its shores one day, Sora and his close friend Riku have been working with her on a raft to explore other worlds in the hopes of finding her home. After gathering supplies to work on the raft, the three friends rest on the beach, discussing the possibility of worlds beyond their own.
Meanwhile, in Disney Castle, court magician Donald Duck discovers that his king, Mickey Mouse, has gone missing. Awakening Mickey's Captain of the Guard Goofy, the two learn that Mickey is investigating the encroaching darkness, and that the only hope to save the universe is a person with the key to their survival. To this end, Donald and Goofy need to go to Traverse Town to find a man named Leon. Joined by Mickey's dog Pluto and Jiminy Cricket, the two set forth to Traverse Town.
Back on the Destiny Islands, Sora continues to help Riku and Kairi find food and supplies for their journey. Sora's mission takes him to the Secret Place, where he had once drawn an image of himself sharing local paopu fruit with her. As he begins to edit the drawing, he meets a mysterious hooded figure, who cryptically warns him that the world is tied to the darkness. However, Sora takes his leave, wondering about the encounter.
During the sunset, Sora and Kairi have a moment to themselves, where she voices her desire to explore the many worlds that are out there. Her words linger in Sora's mind that night, but as he rests in bed, he notices a storm approaching. Worried about the raft, Sora leaves his house to investigate. On the island's shores, Sora encounters dark creatures, which his wooden sword is utterly useless against. He notices Riku waiting, telling him to go help find Kairi, but Riku embraces the opportunity to leave the islands, slowly sinking into the darkness. Just then, Sora is gifted the Keyblade, a key-shaped sword that allows him to cut through the shadows.
With the Keyblade in hand, Sora fights his way to the Secret Place and finds a catatonic Kairi, who flies through him. The island begins to crumble, and Sora encounters the same monster he had encountered in his dream. He vanquishes the beast, but the island collapses, and he is sucked into the vortex...