Scarlet by Marissa Meyer

While Cinder plans a jailbreak, a girl named Scarlet learns of secrets and the danger her grandmother has long faced when her grandmother vanishes. A street fighter named Wolf claims to know where Scarlet's missing grandmother is, but trusting him could reveal what big teeth he has. When Scarlet and Wolf cross paths with Cinder, they must band together if they hope to outrun Lunar Queen Levana. Read a sample.