Shen Wantang, the legitimate daughter of the Hou family who had just grown hair, was accused of marrying Xiao Yan, the eldest son of Prince Jingan, who was rumored to be "old-fashioned, strict and not close to women" due to her mother's last words. She thought she would spend the rest of her life guarding a living Bodhisattva, but after her marriage, she discovered that the prince not only secretly hid his story books and was afraid of the dark, but also pretended to be passing by and handed her a piece of warm osmanthus cake when she was being punished to copy books. In their sweet and delicate daily life, the two turned their arranged marriage into a youth story of two-way secret love.