When the Two Sisters confronted Sombra, he managed to overcome them and free his kin. With an Umbrum army behind him and Equestria's greatest defenders already defeated, Sombra proceeded to conquer most of the known world in the centuries to follow.

With ponies enslaved as servants of their Umbrum masters, Twilight Sparkle's life seemed set from birth. However, when an accident lead to King Sombra finding out about the young mare's growing intellect and burgeoning magical skill, she is sent to the Crystal Capital to serve in the Royal Library. While sad to be parted from her family, it gave Twilight an opportunity to study rarely afforded to slaves.

Of course, their king showing such interest in a mere slave draws the attention of other Umbrum, as while, causing a stir at court. With rebellion growing and ancient threats on the horizon, Twilight finds herself in the middle of events that will shape the world...