On the day of her wedding, Cheng Fangyue, a maid, is brutally murdered by the eldest young lady, Wang Qingluan. Reborn, she unexpectedly gains the ability to hear conversations between Wang Qingluan and the Heavenly Secrets System. She discovers that she is the heroine of a storybook, while Wang Qingluan is a vicious supporting character defying fate to rewrite her destiny. Seeking revenge and protecting herself, Fangyue uses her medical skills and special ability to carefully plot her moves within the Marquis's household. There, she meets the mysterious Third Master Gu Wushang, who suffers from a soul-loss disorder. As they protect each other, affection quietly blossoms between them. Fangyue repeatedly foils Wang Qingluan's schemes and uses her medical skills to treat and save people during a plague in the imperial palace, eventually earning her freedom from slavery. In the end, she joins hands with Gu Wushang to expose the treasonous conspiracy of Noble Consort Liu and Wang Qingluan to usurp the throne. Together, they eliminate the evil conspirators, and Fangyue rises to become a compassionate physician, taking control of her own fate and finding lasting happiness in love.