The Brocade Book Hides the Bright Moon

A concubine, who was treated as a pawn by her family, relied on her photographic memory and secretly run a pen and ink shop to set up an intelligence network in the capital. However, while investigating an unsolved case, she unexpectedly became a "surface couple" with the prince, who appeared to be a playboy but was actually a secret guard. The two of them tested each other and uncovered the conspiracy, eventually turning the world's chessboard upside down.