Forensic doctor Shen Zhiyao signed a suicide note written in blood at the death scene of his predecessor Lin Xu. The handwriting was exactly the same as the unsolved "Red Lips Serial Case" seven years ago. When everyone believed it was a suicide, she found half a piece of nail polish hidden under his fingernails under the autopsy table - which completely matched the characteristics of the unknown corpse submitted anonymously by the funeral director Qi He every month. Forensic assistant Yu Tang concealed her life experience and approached her. Internet blogger Jiang Rui uncovered the dusty code step by step. The silence of former team leader Chen Zhao is pushing the truth into the abyss. Lin Xu has more than one suicide note, each one is a reminder, and Shen Zhiyao is becoming the next person to be signed.
