The Melancholy of Haruhi Suzumiya - Manga
Following the clues in the clubroom, Kyon travels back in time to a familiar place... the same destination he and Asahina visited on last summer's time travel excursion!
Kyon again meets with the elder Asashina, but she has no idea what's caused the future to go awry - erm, to go normal. Stoic Nagato is not surprised to find future Kyon at her door (for the second time that night) and prepares a program that will repair the rift.
But the decision whether to administer it or not lies with Kyon