The author's writing is not good for the first time, please be gentle, because the author has a pineapple heart. This is not orthodox, there are some misnomers, please feel free to comment.
Male protagonist: Xie Xichen and his mother, Concubine Shu, were not favored and went to the Wei Dynasty to serve as the secret guards of the Ninth Princess (undercover)
Heroine: Lin Qingruo. His parents like him very much, but he wants to help his father do things, so he pretends in front of everyone that he doesn't know how to play piano, chess, calligraphy and painting, and is an idiot princess who is arrogant and domineering.
Male Second: Yu Jinnian and Ruby Lin were childhood sweethearts, but something went wrong and they missed it. He is a handsome young man, in the hearts of many women
Sixth Princess: Xie Chuchu. The emperor didn't like them. He only liked the queen and Lin Qingruo, so he was jealous of Lin Qingruo and wanted to take everything from Lin Qingruo.
Lin Qingruo and Yu Jinnian were childhood sweethearts, but later the Sixth Princess's mother's family became too powerful and the Sixth Princess insisted on Lin Qingruo's sweetheart, so the emperor had no choice but to grant her a marriage. Later, the heroine was heartbroken and the hero fanned the flames. Lin Qingruo did something while drinking, and their relationship heated up.
Intention: Everything in the world has already been determined.