A bizarre case occurred in Binhai City: three skeletal corpses were dug up at a construction site, but there were no clothes or belongings at the scene, only a rusty iron school badge. Forensic doctor Qin Ming led his assistant Li Dabao and trace inspection expert Lin Tao to form an "iron triangle" to investigate. As the investigation deepened, they discovered that the three corpses were actually related to three students who disappeared from a rural middle school twenty years ago. Behind the school badge lies a buried past of campus bullying, a silent witness, and a tragic cycle that spans two generations. When Qin Ming's team got closer to the truth, they found that the identities of the perpetrators and victims had long been blurred, and the real murderer was lurking in the current investigation line of sight, preparing to complete the final "trial"...
