Cinder, the cyborg mechanic, returns. She's trying to break out of prison—even though if she succeeds, she'll be the Commonwealth's most wanted fugitive. Halfway around the world, Scarlet Benoit's grandmother is missing. It turns out there are many things Scarlet doesn't know about her grandmother or the grave danger she has lived in her whole life. When Scarlet encounters Wolf, a street fighter who may have information as to her grandmother's whereabouts, she is loath to trust this stranger, but is inexplicably drawn to him, and he to her. As Scarlet and Wolf unravel one mystery, they encounter another when they meet Cinder. Now, all of them must stay one step ahead of the vicious Lunar Queen Levana, who will do anything for the handsome Prince Kai to become her husband, her king, her prisoner.