She was the scapegoat sacrificed by her family. Fresh out of prison, she was handed over to the underground emperor. He saw the wolfish streak in her eyes and bought her life with an astronomical debt, ordering her to get close to his half-brother as his mistress—the heir who was about to marry the princess of the police world. A meticulously planned game of substitution, it's a chessboard for seizing power and also the prelude to revenge.