There's so much story packed into the last few episodes that it's getting harder to write spoiler-free descriptions of them. Suffice it to say that this episode is entitled: "The Secret Revealed! Saki and Soto's Origins." It does what it says on the tin. Oh, and voice actor Ryuzaburo Otomo has another cameo as that crazed, fur-wearing guard with the big mallet. That dude might want to seriously reconsider his signature weapon...