Welcome to (almost) the end of the game. Like most Kingdom Hearts finales, this is where all of the main plot twists and story beats start actually getting explained. Unlike other Kingdom Hearts finale, it's crazier than a Metal Gear story.
If you thought that Birth By Sleep did a terrible job with how it linked the stories of games that chronologically (by release date) came out before it, then wait until you see what they did in Dream Drop Distance. There's no other way to explain how what is about to unfold other then Xehanort being literally clairvoyant, or having a copy of Nomura's notes.
But we'll get more into that in the next episode. For now, the most interesting thing to note is, as we'll note in the next episode, Riku is the true protagonist of this game. Sora is actually the victim of a sinister plot that has been unfolding over the course of the whole game. Despite our constant complaining, the game does a good job foreshadowing that something bad is going on by continuously bringing Sora into contact with Xemnas and Young Xehanort.
Buckle up, we haven't even begun to jump down the rabbit hole.