When the entire Shen family was wiped out, one of the twin sisters was sent to the marquis's estate to become a bride, while the other was taken north to become a general. Three years later, the elder sister awakened the "Heart Mirror" in the depths of the manor, allowing her to hear the true emotions hidden behind lies. On the battlefield, the younger sister gained "Battle Instinct," letting her predict her enemies' next moves. One untangles the hidden schemes at court, while the other hunts for the truth amid the bloodshed on the frontier. When they discover that their enemy may be more than one family, and that the "taboo of the twins" may be the real reason their family was destroyed, the sisters decide to stop hiding. Together, they'll bring down the masterminds lurking in the shadows, one by one.
