Mare Barrow's blood is red—the color of common folk—but her Silver ability, the power to control lightning, has turned her into a weapon that the royal court tries to control. The crown calls her an impossibility, a fake, but as she makes her escape from Maven, the prince—the friend—who betrayed her, Mare uncovers something startling: she is not the only one of her kind. Pursued by Maven, now a vindictive king, Mare sets out to find and recruit other Red-and-Silver fighters to join in the struggle against her oppressors.