Haruhi Suzumiya (Light Novel) Vol. 4 The Disappearance of Haruhi Suzumiya (novel)

WHAT IF YOU WOKE UP ONE MORNING, AND EVERYTHING HAD CHANGED?
It's one week before Christmas Eve, and Haruhi and the rest of the SOS Brigade are gearing up for holiday festivities. But just before the fun kicks off, Kyon, the only "normal" member, wakes up in a weird alternate dimension, one where Haruhi attends another school entirely, Nagato the time traveling robot is just an ordinary human, and Mikuru (the cute girl of Kyon's dreams) doesn't even recognize him--in other words, the SOS Brigade never existed.

The only clue Kyon can find is a bookmark left by the robot version of Nagato, which leads him on a quest back in time, where he once again encounters the events of "Bamboo Leaf Rhapsody," a short story from the previous Haruhi book, The Boredom of Haruhi Suzumiya. This fun and quirky holiday tale is reminiscent of A Christmas Carol and It's a Wonderful Life.