Hired as Emperor's Body Double, Became a Legendary Emperor?

One moment he's an ordinary man, the next he's the body double for a dying emperor in the Great Zhen Dynasty. Zhao Zheng's mission? Play the part of a mediocre ruler while the real emperor recovers. Simple enough—except he's accidentally too good at the job. Before long, he's reformed the government, won the hearts of the people, and become the most beloved sovereign in history. The real emperor is furious, the empress is confused, and the imperial harem is in chaos. When pretending becomes reality, can a fake emperor outshine the original?