Gu Pan, a history college student, discovered an unsent ancient letter while sorting out his grandmother's belongings. The moment he touched it, he was drawn into a time tunnel and traveled to the fictional Dajing Dynasty, where she became the unpopular legitimate daughter of the general's palace. When she first arrived, she bumped into Xiao Jue, the rumored cruel and ruthless Prince Jing. She thought it was a bad fate, but she didn't expect Xiao Jue to defend her at all times, "Whoever dares to touch my people will be killed without mercy!" Gu Pan gradually fell into defeat, but found that this ancient letter actually contained the agreement between the two that spanned a hundred years...
