While simultaneously trying to prevent and prepare for war between the Faeries of the Night and Faeries of the Light, Queen Holly Blue is kidnapped from her Uncle Hairstreak's home by human Henry Atherton and learns she must face another, far greater enemy.

Stubborn and feisty Mella, the half-faeire half-human daughter of Lord Henry and Queen Holly Blue, has the power to determine the fate of both the faerie and "analogue world" when she travels to the country of Haleklind and discovers rebel forces preparing for war.

When a terrible plague takes over the faerie realm and causes its inhabitants to age unnaturally quickly, Henry and Blue must find a cure in order to save the realm.