Sunset Shimmer has fled back to Equestria, forced out of place by her double. The local versions of her friends try to make her feel comfortable, but Sunset is upset and scared. Worse still, she's becoming unstable again. She didn't come back alone.
A dalek appears in Equestria - not just any dalek, but the one that had been corrupted by Rose Tyler's DNA. It has a choice of life as a pony, or dying, and finds that it cannot bear to die a second time. Thus begins a strange adventure...