The second book in The Lunar Chronicles series by Marissa Meyer.
This is not the fairytale you remember. But it's one you won't
forget. SCARLET BENOIT'S grandmother is missing. The police have
closed her case. The only person Scarlet can turn to is Wolf, a
street fighter she does not trust, but they are drawn to each
other. Meanwhile, in New Beijing, Cinder will become the
Commonwealth's most wanted fugitive - when she breaks out of prison
to stay one step ahead of vicious Queen Levana. As Scarlet and Wolf
expose one mystery, they encounter Cinder and a new one unravels.
Together they must challenge the evil queen, who will stop at
nothing to make Prince Kai her husband, her king, her prisoner . .