When Seraphina, a Chinese-American traditional Chinese medicine practitioner and anti-fraud internet celebrity, livestreamed to expose weight-loss drugs containing aconitine, the oath she swore—"I’ll gain two hundred pounds if I’m wrong"—came true, sending her transmigrating to the Orendia Empire. She wakes as the framed, overweight illegitimate daughter of a noble house, forced into a political marriage with Crown Prince Elias, who is trapped by scheming ministers.
She knocks the prince unconscious, claims him as hers, steals his gilded crest, and flees while pregnant. Hiding out at Blackraven Fort (later renamed Holy Light Fort), she makes a living practicing medicine. Five years later, she has slimmed down and raised twin sons and a daughter. Her youngest child Leah stumbles upon and saves Elias after an assassination attempt, revealing the truth of their maternal bond. The crown prince at last tracks down his runaway wife.
