With the Westerners and their allies pressing in on all sides, the empire of Great Liang enters its darkest hour. Under these desperate conditions, Gu Yun leads the beleaguered Black Iron Battalion to hold the borders. Meanwhile, Chang Geng makes his move in the imperial court, sweeping corrupt officials aside in an effort to stabilize the nation before it's too late.

As the two struggle to hold the tattered pieces of the empire together, Gu Yun uncovers a shocking truth about the curse slowly tightening its grip on Chang Geng's mind. But are the deepest secrets of Cheng Geng's past enough to move even the iron heart of the nation's most fearsome general?