The play is adapted from Qin Ming's literary work "Silent Testimony". It tells the story of Qin Ming, a talented young man who has just started his career. With the help of Lin Dang and others, he gradually walks out of the haze of childhood memories and grows into a forensic master who can control the overall situation. 15 years later, a case with the same characteristics as the homicide Qin Ming experienced 15 years ago happened again in Longfan City. Was it an imitation crime? Or was the wrong person arrested that year? Or did the murderer have another accomplice? The nightmare of the old case was turned up again, and the heart knot was constantly troubled. Lin Dang, who broke into the scene, often caught Qin Ming off guard... The iron cage corpse case, the "League of Thieves" case, and the "Death Knight" case occurred in succession. In the end, his own biological father was actually involved in the vortex of the case... The memories of the year emerged in his mind little by little, and the murderer surfaced at any time...