Lin Chen, a top student in the modern police academy, accidentally traveled to the newly liberated Peiping in 1949 and became the first batch of policemen in New China. With the "Public Security Assistance System", he uses future fingerprint technology, surveillance principles and other criminal investigation methods to help solve strange cases and fight crimes in complex situations where spies are lurking and cases occur frequently. He uses modern police wisdom to build a secure defense line for the new city and write a police legend that spans the ages.
