Shen Du has a secret - he can hear the "heard sound" of anything he touches with his hand. An old wooden door will retell to him the conversations that everyone has had in front of it for decades, and a mirror will tell him where the last person who looked at it went. After the police asked him to help solve a cold case that had been silent for seventeen years, an unknown number sent him a text message: "The last words you hear will kill you."
