Theodore Blackmoor is the tenth hero sent by the Sunsworn Order to kill Ravenna Nightshade, the woman feared throughout the Vale as the Villain Queen. Raised to believe that Ravenna is a ruthless tyrant, Theodore expects to face a monster.

Instead, he discovers a queen who has spent twenty years protecting her people from a war she never wanted—and wearing the mask of a villain because it is the only thing keeping her enemies at bay.

Ravenna offers Theodore a choice: serve the Shadowmarch for one year or remain her prisoner. But as he learns the truth behind the war, his loyalty to the Order begins to crumble, and something far more dangerous takes its place: love.

When Theodore returns to the Vale and is imprisoned for speaking the truth, he risks everything to escape and return to Ravenna. Their reunion changes the course of both kingdoms, but their love soon becomes the most dangerous weapon in a political war engineered by Oberon Dreadmoor, a powerful general determined to destroy the fragile peace.

Now Theodore and Ravenna must stand together against enemies on both sides of the border. To end a twenty-year war, the hero must choose between the kingdom that raised him and the woman he was sent to destroy.