Lucy, a young girl living in isolation on an island, hears beautiful music one day. Singing to it, she discovers herself suddenly in London--she is a Chantress, a singer of magic spells. Only she is untrained and does not know the danger she is in from the Lord Protector, who eradicated all Chantresses he could find when he came to power. Teaming up with Nat and his Invisible College, Lucy finds her heart throbbing for him--but it may cost her her life.