Kingdom Hearts: Chain of Memories is set immediately after the events of the first game. It is set in Castle Oblivion, a mysterious castle kept by Lord Marluxia. Sora and his teammates are told that the castle causes visitors to lose their memories upon entering. The lobby and areas between floors are white with flower-themed decorations, but each floor can be transformed into a different world from the first Kingdom Hearts game using "world cards" created from Sora's memories. (wikipedia)