Starlight Glimmer is about to get her revenge on Twilight and her friends, she just has to stop that cyan pegasus from doing her rainbow trick. But before doing so, she receives a visit from a Doctor.
The Doctor finds himself in Equestria following a violent regeneration and is forced to work alongside an annoyed Twilight Sparkle in order to defeat an old enemy.
Twilight, Rainbow and Applejack travel 3000 years into the past with their new friend the Doctor, to the ancient city-state of Roan. They meet the famous Leonard DiHoovsie, and find themselves embroiled in a deep mystery with dark implications.
After the harrowing events of "Traveller," the Doctor is forced into having some downtime in Ponyville while the TARDIS rests. Meanwhile, Twilight goes to confide in her beloved mentor, but ends up learning far more than she expected.