The world is cracked and in ruin. The air is full of dead men's ashes, fallen colossi smother the earth with their decayed husks, and infectious monsters roam freely. In their desperation, a group of alchemists have created a killer named Sym from obscene magic, outfitting her with an engine that will allow her to travel back in time to stop whatever it was that made their world so. But the alchemists don't realize that the engine is sentient, that their unstoppable killer is powered by the seed of their destruction.