After discovering some more of Star Swirl’s unfinished spells, Twilight's curiosity causes her to cast one, in spite of Spike's warnings. To her surprise, the spell doesn’t seem to do anything. Frightened that perhaps she repeated her previous mistake from Magical Mystery Cure, she rushes to Ponyville only to find everything is as it should be. After this, she agrees not to try to fix any more spells and goes to sleep...
Only to wake up in the past.
Using this opportunity, she begins to correct past mistakes. There are some setbacks, but overall Twilight believes she is making the world better.
Yet as she seeks to fix the problems of her past, she will find that sometimes past mistakes are exactly what our future needs.
For those wondering about continuity with events in the show, chronologically, I'd say the events take place just before the episode Filli Vanilli. The basic outline of this story was actually planned out before season 4 began and much of it was written before the end of season 4.
This fiction was featured on Dec. 9, 2014 - Now that's a great Hearth's Warming present. Thanks guys. 
If you want to know more about the writing process for this story, you can check out my blog post More About "More About Time" for, well, more about this story.
20 Chapters:
-
Prelude: Discovery of the Century [Fimfiction.net] [Cache]
Jun 9th, 2017
3,405
-
Chapter 1: Authoring a New Future [Fimfiction.net] [Cache]
Dec 7th, 2014
2,945
-
Chapter 2: Dashing Toward Tomorrow [Fimfiction.net] [Cache]
May 28th, 2015
3,877
-
Chapter 3: An Uncertain Past [Fimfiction.net] [Cache]
Apr 25th, 2016
2,936
-
Chapter 4: Dreams of Yesterday [Fimfiction.net] [Cache]
Jul 28th, 2014
4,218
-
Chapter 5: Profits of the Present [Fimfiction.net] [Cache]
Dec 7th, 2014
5,432
-
Chapter 6: Unexpected Sunrise [Fimfiction.net] [Cache]
Dec 7th, 2014
3,482
-
Chapter 7: The Truth of the Moment [Fimfiction.net] [Cache]
Dec 7th, 2014
3,719
-
Chapter 8: Heading into Dusk [Fimfiction.net] [Cache]
Dec 7th, 2014
2,965
-
Chapter 9: An Unsettling Evening [Fimfiction.net] [Cache]
Dec 7th, 2014
3,559
-
Chapter 10: Languishing at Sundown [Fimfiction.net] [Cache]
Aug 31st, 2016
3,540
-
Chapter 11: Struggles of Twilight [Fimfiction.net] [Cache]
Dec 9th, 2014
4,898
-
Chapter 12: Wandering by Moonlight [Fimfiction.net] [Cache]
Apr 5th, 2015
4,764
-
Chapter 13: The Long Night [Fimfiction.net] [Cache]
Mar 28th, 2016
5,078
-
Chapter 14: Looking for Daybreak [Fimfiction.net] [Cache]
Apr 5th, 2015
4,564
-
Chapter 15: A Welcome Dawn [Fimfiction.net] [Cache]
Apr 8th, 2015
4,091
-
Chapter 16: Working Against Time [Fimfiction.net] [Cache]
Apr 12th, 2015
3,701
-
Chapter 17: The Timeless Season [Fimfiction.net] [Cache]
Jun 19th, 2016
3,564
-
Chapter 18: Just Today [Fimfiction.net] [Cache]
Jul 21st, 2016
3,965
-
Epilogue: From Another Millenia [Fimfiction.net] [Cache]
Jul 21st, 2016
2,719