In a frenetic quest to reunite himself with his lost love, Dr. Horrible finds a kindred spirit in the most unlikely of places: a mare who, like him, once turned to hate in search of love. Meanwhile, Bad Horse suspects that Dr. Horrible is going soft. And if Dr. Horrible gets on Bad Horse's bad side… well, that's something Dr. Horrible would rather not think about. Warning: contains Dr. Horrible spoilers.