In the novel “Death at the Threshold,” a war of fairies begins, and the main heroine finds herself at its center. Her father, King of the Unkind, has died, and now she must hide in London from her enemies. To stand against them, she needs to unite the six houses of the Unkind, but long-standing feuds make that almost impossible. Moreover, her magic of fear is gone, and now she has to decide where she will live—among humans or among the fairies. The Kind brutally destroy both fairies and people, and she must get her magic back in order to fight them.