A modern poison doctor transmigrates into Feng Ci, the legitimate daughter of the Feng family, who was poisoned to death by her stepmother and the Crown Prince. Awakening an ancient alchemy art, she launches a powerful revenge. With her medical skills and strategic brilliance, she tears away her hypocritical stepmother's mask, brings down the ruthless Crown Prince, and reclaims control of the Feng household and the position of family head. With the help of her covert guard Tingfeng, the powerful Ye Xuancheng, and the medicine-obsessed Elder Yao, Feng Ci heals people with alchemy and breaks through crises with her intelligence. Amid the power struggles of the imperial court, she defies fate and ultimately becomes the power behind the scenes, overturning the decayed court and transforming from a legitimate daughter seeking revenge into a poison queen who wields power.