Xie Yan was sent to death prison as a mental illness. Three months later, the autopsy report showed that there were three unexplained toxins in his body. During the autopsy, forensic doctor Su Lin discovered that there were unrecorded neural implants in Xie Yan's brain tissue - exactly the same as his brother's corpse three years ago. The code carved in the corner by the deaf-mute prisoner Chen Ya points to a living experimental subject code-named 'No. 7'. Nurse Lin Que secretly recorded the details of every 'natural death', only to discover that the drugs she delivered every day were slowly reshaping the prisoners' consciousness. When the autopsy report exploded across the Internet, the real hunt had just begun.
