Datang: at the Beginning, Li Er Was Mistaken for His Father-In-Law.

Chu Xuan traveled to the Tang Dynasty. Chu Xuan, who has been bound to the daily sign-in system and has been an idler for several years, is preparing to fulfill his father's marriage arrangement. According to the engagement, Chu Xuan came to propose marriage, but mistakenly thought that Li Shimin and Empress Changsun, who were traveling incognito, were his father-in-law and mother-in-law. Chu Xuan: "Father-in-law, these are potatoes, which can solve the famine in the Tang Dynasty. You can sell them to Li Er and take the opportunity to kill him!" Li Shimin: "...!" Chu Xuan: "Father-in-law, this is a Quyuan plow, which can double the harvest of farmers in the Tang Dynasty. You can sell it to Li Er and take the opportunity to kill him!" Li Shimin: "...!" Chu Xuan: "Father-in-law, this is a horseshoe, which can enable our cavalry of the Tang Dynasty to roam across the grassland. You can sell it to Li Er and take the opportunity to kill him severely!" Li Shimin: "...!" Until one day, Chu Xuan was granted the title of King and entered the palace to meet the saint. Li Shimin smiled and said: "My good son-in-law, come and see who I am?" Chu Xuan: "...!"