At 17, Mao Mao has a complicated life. Trained from a young age by an apothecary in the pleasure district, she is kidnapped and sold as a servant in the imperial palace's women's quarters! Surrounded by high walls, she is cut off from the outside world. To survive in this luxurious prison teeming with conspiracies and low maneuvers, the young girl tries to hide her knowledge to blend in. But when the suspicious deaths of newborn princes stir up the court, her passion for poisons takes over. She observes, investigates... and finds the solution! In trying to do good, she gets noticed... Jinshi, a high official as handsome as he is calculating, senses her talent and promotes her to personal taster for one of the emperor's favorites. In the middle of this nest of vipers, the slightest misstep could be fatal to her!