To break through the family's predicament, Lin Xianxing recommended herself to enter the Danyang Princess Manor, suddenly becoming a county princess of the early Ming dynasty. The stern and murderous eldest brother Rong Yanxiu, along with three other brothers, all hold her in the palm of their hands. Undercurrents surge in the Yingshe Department, years-old cold cases are shrouded layer upon layer, and cold poison, statecraft, and crisis follow one after another. Relying on her intelligence and quick wit, she maneuvers among various forces, protects each other with her brothers, and goes together to Mangzhou to uncover the truth sealed for many years.