In the autumn of the ninth year of Wude, undercurrents surged in Chang'an City. After the Xuanwu Gate Incident, although Li Shimin ascended the throne and proclaimed himself emperor, he was deeply trapped in the shadow of court suspicion and blood feud. During a private visit incognito, he was actually stopped in the street on Zhuque Street by a young man named Li Xiuer who claimed to be a "son who had been separated for fourteen years." A drop of blood was used to test the relationship, and the blood blended together - the whole court was in an uproar.
