After an abnormal magical discharge, a strange mare wakes up inside Canterlot Castle, with no memory of who she is or where she came from.

The Royal Princesses puzzle over this stranger, not because of her unknown origins, but because of the two large horns growing on the sides of her head.

In the Frozen wastes north of the Crystal Empire, lives a reclusive earth pony. Haunted by things done in the past, he seeks to hide away from civilisation. Sensing the arrival of the strange mare, he realises his past has come to catch up with him.