Continuing on his journey to find Kairi, Sora comes across an evil scientist in possession of a key-blade. Not only that, but the magical masks that populate the world know of the worlds outside their own. Now he has to stop Dr. Neo Cortex and Uka Uka, not just from taking over the world, but taking over all worlds. (Continues from Kingdom Hearts: Lets Just Live and The Protector)

When a new threat of evil is threating the very exisitance of reality, it is up to Sora and the gang to save the day once again. However this time, things become much more complicated. With the rise of new threats, comes new challenges and facing off against new, dangerous enemies. Although, they have the support of new heroes who are forced into this battle also.

Xion arrives in a new world for recon and meets a strange, largely silent inhabitant. She unknowingly creates another connection.