A simple story about a mare, formerly known as Lunette (a gallifreyan time lady) but now known as Miss star, or, most commonly, Starry pearl. Together with her trust companions, Alex and Terri, as well as a few new acquaintances and an encounter with an old friend, they travel to a point in time where only they can solve this puzzle.
Basically, in a nutshell (Mega spoilers!) Starry pearl/The professor/Lunette meets an old friend which she met during the time war of gallifrey. Alongside two new companions, she meets some old enemies of hers, the Weeping Pegasi. The only problem is: They're back. And stronger than before. There is no way to stop them.
.....Right?
This story takes place after the episode "the mane attraction".
Featuring Dr whooves, hence the crossover tag.
(FYI, Dr whooves is a pegasus in this. Derpy is named Ditzy Doo aswell.)