Long ago when the Celestial empire was just starting there was a fourth alicorn. This alicorn was the king of storms. He had the ability to summon devestaing storms the likes of which leveled cities. This ability was lost upon his defeat, it returns
Imagine an Equestria where robots and cyborgs wander the streets as normally as any pony. Then imagine irresponsible nobles causing crime to rocket out of control. This is Shadow's world, and the young lunar pegasus will now stem the tides of evil.