A ring, a mysterious time travel. Li You, a young man from the 21st century, was actually transported into the Tang Dynasty and became Li You, the Prince Qi, whom Li Shimin called a scoundrel son. What's even more troublesome for this time traveler Li You is that he traveled to the 17th year of the Zhenguan era, the year of Prince Qi You's death. In this year, Prince Qi You will be the only son of Li Shimin who was executed for rebellion. "What's going on..." The time-traveling Li You cried bitterly, rebellion? No rebellion? What to do, the time-traveling Li You was lost and confused. However, at this time, the time-traveling Li You suddenly found that there seemed to be something wrong with his ring...