Shen Qingwu, the county magistrate's eldest daughter, can use an abacus to bring order to thousands of acres of farmland, but she can't calculate her own romantic fate. Then the low-profile prince investigating a case crashes into her world, taken aback by her quick wit. He presses forward at every turn, and she meets each move with one of her own, while the divide between their social ranks looms like a mountain. But when the account books uncover a massive conspiracy, she realizes this game has long since become about more than marriage...