Viva Las Pegasus tells the story of Farsight, a Stable-Pony cast into the wilderness of the wastes. The City of New Pegasus remained unharmed by the bombs and the Megaspells, and has been growing ever since. Beneath the city lights, the dwellers of Stable 188 live their lives ignorant of what lies above. Once a year, a dweller gets cast away into the Wasteland. Meet Farsight, a pony from the Stable 188, who suffers such terrible fate, and watch him rise to power in a post-apocalyptic mobster world... just to fall back into oblivion.
The story takes place in the Neighvada Territory, 20 years after the Day of Sunshine and Rainbows. However, because of the effect of a magic barrier created by the megaspells (the Divide), Neighvada hasn't profited of the healing effect of the Gardens, and keeps being a barren Wasteland where Raiders roam freely.