Equine Impact takes place in the fantasy world of Equestria, home to seven nations, each of which is tied to a different element and ruled by a different god. The story follows The Traveler, an interstellar adventurer who, at the start of the story, is separated from their twin sibling after the two land in Equestria. Thereafter, the Traveler journeys across the nations of Equestria in search of the lost sibling, accompanied by their guide, Deco. Along the way, the two befriend myriad individuals, become involved in the affairs of its nations, and begin to unravel the mysteries of the land.