Three Londoners die and wake in a world built on stolen dragon power, a world with no dragons left in it. One of them, Harry, comes to in the dying body of a murdered dragon-prince, and the rightful owner is still inside. A disc of red runes cools over a stolen heart; while the runes hold, the sealed power stays quiet. When they fail, he becomes a monster in front of the woman who wanted her son back and got a stranger instead.

To stay alive, Harry must hold down the prince, the source-dragon sleeping in the same flesh, and at last the truth that he has become a cage. The story climbs from body horror and palace knives into oppressive empire and contested identity, toward a final reckoning: he can only save the world by opening his hand and giving back what was never his.