While lying in bed next to her husband one night, Claire hears a low hum that he cannot. And, it seems, no one else can either. This noise begins causing Claire headaches, insomnia, gradually upsetting the balance of her life, though no medical cause can be found. When she discovers that a student of hers can also hear the hum, the two strike up an unlikely and intimate friendship... A speculative novel exploring the fine lines between faith, conspiracy, and mania in contemporary America.