Special forces soldier Chu Yang accidentally time-travels and becomes a body double for the Ninth Prince of Great Xia, forced to complete the bridal chamber duties for the real prince. Just as he activates a cheating system, the real prince turns on him and tries to silence him after the deed is done. Chu Yang decisively kills and overpowers his opponent, takes on the prince's identity, and persuades concubine Shen Youwei to keep his secret. Before the turmoil settles, court disasters follow one after another; the original owner was framed into writing a frivolous love letter, angering Zhao Yunying, a fierce and valiant female war goddess who wields heavy military power. Facing the princes' schemes, the emperor's interrogation, and the princess consort arriving in the capital to hold them accountable, the fake prince Chu Yang will rely on the system and his own skills to rise step by step amidst the perilous vortex of the struggle for the succession.