The disappearance of Haruhi Suzumiya

On December 17th, everything was as usual—school, the approaching Christmas, and Haruhi's idea to throw a party. But the next day, Ken wakes up in a completely different world: Haruhi has disappeared, Nagato has become an ordinary quiet schoolgirl, Mikuru is also without abilities, and the mysterious transferred student never existed. Reality has changed, and only Ken notices it.