I Want to Be the Emperor of the Song Dynasty

Once in time, Yue Yun, a national defense college student, traveled from 2018 to Yue Yun more than 800 years ago. This Yue Yun is not the other Yue Yun. Although he served the country loyally, he served the country of China. Since Zhao Song will die sooner or later, let me be the emperor. At least I can try my best to reverse history and save China from being massacred by the Mongolian and Yuan cavalry.