Centers around experiments on a disembodied, living female head. This is one of only a small handful of horror films produced by Mainland China in the 80s since genre films were banned there until the late 80s.
The Public Security Bureau intercept a telegram notifying foreign agents to retrieve the "110 secret". Shi Yan, head of the Reconnaissance Section, starts a campaign of counter-espionage, but one of his agents is soon killed on board a train.