Three Black Triangles

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.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.