Sora’s Story
Sora, Donald, and Goofy are traveling down a long and winding road in search of Riku and the King. When they stop to rest, Sora is unable to relax, and so he wanders ahead alone. He encounters a mysterious cloaked figure who tells him “Ahead lies something you need. But to claim it, you must lose something you hold dear.” Sora, Donald, and Goofy follow the cloaked figure to a strange fortress known as Castle Oblivion. Upon entering the castle, Sora and his friends instantly began loosing memories of their previous adventure, and were introduced to the way of things in Castle Oblivion.
The cloaked figure explains that in this castle, to find is to lose, and to lose is to find. He also explains that everything in this castle is ruled by the power of the cards, which could be used to open doors or fend off enemies. Sora uses the first card and enters the door, but on the other side was a whole new world – Traverse Town to be precise. Sora soon learns that each card is crafted from his memories and the various worlds he visits are nothing more than memories of places he’s been.
Upon leaving Traverse Town, Sora meets Axel, who appears to be working with the cloaked figure. Axel tests Sora’s strength and gives him a group of cards that will allow him to advance through several more floors of the castle. Be he warns him that when his sleeping memories awaken, Sora may no longer be himself. Sora presses onward through the different worlds the cards create.
As he makes his way through the castle, Sora begins to remember another girl from his island home, though he cannot remember her name. He pushes forward until he meets Larxene, another ally of the cloaked man. Larxene forces Sora to remember the girl’s name, Naminé, and confronts him. When Sora emerges victorious, Larxene hands over another batch of cards, allowing Sora to move on.
As Sora continues, he encounters Riku, who doesn’t really appear to be himself. He’s sworn to protect Naminé and battles Sora for the right to do so. They clash many times as Sora progresses through the castle. When Sora reaches the Tenth Floor, he meets Vexen, another member of the mysterious Organization, who intends to defeat him. When he is unsuccessful, he hands over a card crafted from the memories on the other side of Sora’s heart. This card brings Sora to a world he’s never been to, but one that feels familiar to him. When he finds Vexen again, he confronts him for a second time. Sora emerges victorious, and Axel intervenes to silence Vexen permanently before he can ruin the Organization’s plan.
Despite the fact that Vexen is gone, Riku is still intent on fighting Sora for the right to protect Naminé, even though they both want the same thing. Sora presses on, and finally meets Naminé, only to find out that she was never really a part of his memories, and there was another girl who he had made a very important promise too. Riku steps in to try to finish off Sora once and for all, and after their skirmish, Naminé breaks Riku’s heart before Larxene appears. She explains that the Riku Sora has been fighting this whole time was nothing more than a fake created by Vexen picking fights over memories that weren’t real. She also tells Sora about Naminé’s power over his memories, and how she can manipulate them to make Sora think whatever she wants.
Sora, infuriated that Larxene would threaten Naminé even if his memories were fake, challenges her and defeats her for good before moving to the final floor to take on Marluxia, the cloaked figure he had met out in the fields outside the castle. Naminé also explains that if they can defeat Marluxia and make it to the final floor, she’ll be able to fix everyone’s memories.
Meanwhile, Axel has revealed his secret intentions of stopping Marluxia from taking over the rest of the Organization. The two of them clash, and when Marluxia threatens to use Naminé as a shield against Axel’s attacks, Sora intervenes to take Axel down. They fight and Sora moves on to find Marluxia deeper in the castle. After Marluxia is defeated, Naminé explains that Sora has a choice to make. He can either regain his memories of his past adventure and lose the ones of Castle Oblivion and herself, or lose the memories he had before and keep the ones he has of the castle. Sora chooses to have Naminé put him back the way he was before he entered the castle, and she explains that he, Donald, and Goofy need to sleep in special pods while she fixes their memories. While in the pod, Naminé tells Sora that if he can remember the promise he made to the other girl, the rest of his memories will come back much faster. When Sora remembers Kairi, the rest of his old memories start rising out of the darkness of his heart and into the light, where Naminé begins to piece them back together.
Riku’s Story
Riku finds himself floating in the Realm of Darkness when a light appears offering him a path to the truth. Riku follows the light to the basement floors of Castle Oblivion, where he begins to encounter the dark characters from his memories. He soon learns that Ansem still lurks within his heart and he must fight off the remnants of darkness that still linger in his heart. As he proceeds, he meets Vexen, who manages to gather enough data on Riku to make a replica who will think and act the same way the real Riku would. As Riku makes his way further into the castle, he confronts the Replica, who then retreats back to the upper floors of the castle.
Riku presses on until he meets Lexaeus, another member of the Organization. They battle, and when Riku defeats Lexaeus for good, he presses on. Riku then meets Zexion, who tries to deceive Riku by tricking him with illusions of his own memories, but Riku is able to see through these illusions and Zexion is forced to retreat, only to be destroyed by the Riku Replica.
Riku encounters DiZ, who offers him a choice. He must meet Naminé, and then choose to fall asleep or continue to fight the darkness inside him. He decides to continue on and Riku clashes with his Replica once more. When he emerges victorious, the Replica fades away, and Riku continues to the final Basement Floor to confront Ansem for the last time. He defeats him and meets DiZ once more. DiZ offers him two paths, one on each side – the road to light, or the road to darkness. Riku chooses to walk neither path, but rather, he walks down the middle path – the road to dawn.