After the events of Cutie Re-Mark, Starlight makes the mistake on telling Sweetie Belle & Scootaloo about the map and how to use the time travel easily. Now these two are travelling though out time to try and save the future.
When Twilight is having breakfast with her friends, she finds a spell from Starswirl the Bearded that can make her travel through time, but every cause has consequences and every change in the past can alter the future.
Starlight Glimmer destroys Equestria when she learns how she actually lost her soulmate, Sunburst. Fixing her mistake, she learns time travel can lead to a revelation of the heart and the renovation of harmony. (An alt-ending to The Cutie Re-mark.)
Luna is through with Celestia making excuses for why ponies don't love her. A dark monster appears, promising to change that. But who is this Nightmare Moon? Why does she bear Luna's mark? And why is she so confident in her vision for the future?
Twilight Sparkle is perfectly happy with her dateless Hearts and Hooves Day. Just because all her friends have dates and she doesn't. What does that matter?
Time traveling from five thousand years in the future, Twilight Sparkle—or as she prefers, Glitter-Flanks—has one mission: to establish the closed time loop that sets her and Celestia up as a couple, by flirting as aggressively as possible.
My special talent had turned my life into a waking nightmare of moral and life-or-death decisions. I hoped visiting cousin Apple Bloom, who'd survived her own cutie mark nightmare, might help me decide whether to keep my cutie mark... or remove it.
Twilight is awoken early in the morning to Rainbow Dash knocking on her door. The pegasus seems out of sorts, and this only becomes more apparent as time goes on. What could be wrong?
A young mare with a dark secret learns of something that will shatter her world forever- she is stuck, destined to repeat the same day for all eternity.
What if Cadance hadn't stepped in and stopped Twilight from thinking about breaking the laws of physics and causality to spare Spike a little embarrassment at the Equestria Games? Nothing good.
Twilight Sparkle definitely learned her lesson from her last time-travel experience. This one's not her fault. Really. Sometimes nature can be... annoying.