Sơn applies to clerk for a director at a research institute but is instead assigned to spy on Linh, the director's beloved daughter. Offered a generous sum of salary while still struggling a secure a job, the young man happily undertakes the peculiar duty with great prudence, much to Linh's chagrin.

A poor carpenter hopes to secure a better life for his daughter by sending her to a college in Hanoi. As the university entrance exams approach, he is dead set on the ultimate mission: ward off anything - or anyone - that will distract the daughter from studying only.

The film begins with an assassination attempt at the private clinic of psychologist Tran Ngoc Tam. A criminal investigator named Sang is assigned to the case to investigate and delve deeper into criminal psychology. During the process, another murder occurs: the death of Dr. Tam's secretary. Through Tam’s cooperation, Sang uncovers a drug trafficking and manufacturing ring. Assisting Sang in this special task force are Long, a scout from the anti-narcotics unit, and a cabaret dancer named Hang Nga