Humanity has made a mistake. An honest one! But... also, a very costly one. Our first extrasolar probe, the Pioneer 10, was believed dead, likely destroyed by some micrometeorite. No one on Earth paid it much mind. The ponies of Equestria were not so lucky. Outraged by an unprovoked attack, Twilight Sparkle and Luna turn the planet of Equus into a mighty war factory, and bring their wrath down upon an unsuspecting Earth.