A week before Christmas, Kyon wakes up in a world where the SOS Brigade doesn't exist. Mikuru and Yuki don't recognize him, and Haruhi and Itsuki seem to have vanished.
Anna, a shy 12-year-old girl, is sent to spend time with her aunt and uncle who live in the countryside, where she meets Marnie. The two become best friends. But Anna gradually discovers that Marnie is not quite who she appears to be.