Here's what I think will be the overall storyline of KH III should be:
Sora, Riku and Kairi arrive in a beautifully restored Radiant Garden, no longer fearing the Heartless. But that's all shattered when Maleficent returns, directing her actions from a newly gothic Castle That Never Was. Sora is worried about Disney Castle's safety now that the Heartless are back, and arrives to find the castle deserted, except for three mysterious silver haired teens (Kadaj, Yazoo, and Loz) who refer to Riku as "little brother" and try to capture them using pure Hearless (without emblems) Realizing the situation is worse then they thought, they flee the castle and head off into other worlds to find Disney Castle's occupants, while defeating Maleficent's allies and evading the Kadaj's gang. Eventually they find The Disney Castle crew, and defeat Maleficent.
Back at Radiant Garden the Remnants are attacking. Sora's group defeats all of the Heartless thrown at them, and confront the Remnants. During the battle, Kadaj finds true Darkness, transforming into Xehanort (Ala Advent Children, but different). Xehanort proffesses to be Riku's uncle, but Riku still shows no mercy. Xehanort is defeated, and three strange Knights come and capture Yazoo and Loz (Kadaj is dead) King Mickey speaaks to the knights as if he knows them. Sora questions Mickey, but the king tells nothing. And so another journey starts.
