The Great Overrun has happened, and all of the world's monsters have taken to the streets and are wreaking havoc. Cora's father, Kostros Minot, is a monster hunter who devotes all of his time to keeping his suburb of Phoenix, Arizona monster free. With his wife missing, he is teaching his daughter, Cora, the trade. Cora must deal with trying to meet her father's expectations, her mother's disappearance and just trying to stay alive. Cora, her father and their motley band of fighters must convince the heads of each group of monsters that your past doesn't define you, and it is never too late to make a positive difference in the world, no matter what harm you have done.