Yi Fan came to the Tang Dynasty with a mobile phone and a cow. In order to survive in this world, he used his mobile phone to show Li Er a video, pretending to be the apprentice of Taoist Lao Tzu. Using his knowledge spanning thousands of years, he transformed the Tang Dynasty. If Li Shimin treats him well, help him build an empire on which the sun never sets; if he treats him badly, kick him out and do it alone. Hmph! Hmph!!!