
Films in the series include:

The film series stars Simon Yam, Maggie Shiu and Lam Suet.

"Partners" is the last film in the film series.

The film revolves around the criminal underworld of dark skinned non-Chinese, and discrimination by Chinese against the darker skinned non-Chinese, with the PTU and CID investigating a criminal plot by an Indian criminal kingpin.
"Comrades in Arms" has been featured in the 2009 Hong Kong Film Panorama in Brussels, the 2009 New York Asian Film Festival of New York City, the 2009 Zero em Comportamento festival of Lisbon, and the 2009 Fantasia Festival of Montreal.
The film deals with the rivalry of the two PTU columns commanded by May and Sam, as May has been proffered a promotion, and Sam has been in the field much longer, and the actions of their commander, Ho in preferring May's column over Sam's in their PTU platoon. Their rivalry leads to disrupted interaction and communication when many PTU units are used in a search for a gang of criminals holed up on a forested mountain.
"Human Nature" focuses on the always-in-debt CID officer Tong, and his travails to try to repay the debt he owes a loanshark. With his feeble attempts to repay the debt, he gets himself entangled with a gang of killers from mainland China, who are out killing criminals to rob them of their money, and using an ideological basis to justify the killings as protecting mainland China from the criminal scum of Hong Kong.
"No Way Out" is the second sequel to the original PTU.
The film focuses on the retarded Fai and his girlfriend, rather than the members of the PTU, and life in the Temple Street district. It follows Fai, as he is physically coerced to do things by the PTU, and two rival triads, and the resultant consequences and violence that is paid in return for those actions.
"The Code" has been featured in the 2008 Far East Film Festival of Udine; it is the first entry spun off of PTU. The script for the film was written by Yip Tin Shing.
The film focuses on the aftermath of an unreported beating meted out by a PTU column on a person in a back alley that was caught on a camera placed by the tourism bureau. The West Kowloon Police Station comes under investigation by an investigative committee of the police, as the film follows various members of the police with different motivations try to find the person who was beaten, to settle different goals, with a subplot of another member of the PTU having gotten into administrative trouble before the investigation began and having difficulty dealing with it.
"Into The Perilous Night" has won many awards. In 2004, it won five awards at the ninth annual Golden Bauhinia Awards. It also gave Johnnie To a Best Director award at the 2004 Hong Kong Film Awards. The film has also been featured in many film festivals. It was shown at the 2003 St. Louis International Film Festival; It has a score of 57% at RottenTomatoes.com
The film focuses on the aftermath of CID Lo losing his service revolver, and the night that follows, with PTU patrols and rival criminal gangs seeing action on the street in the climax of the film.
In addition to the official entries in the series, as in Hong Kong tradition, other films have been named with similar titles, to take advantage of the fame and popularity surrounding PTU, which have no relation to the series at all.
One of these is "PTU女警之偶然陷阱" (PTU File – Death Trap) from 2005, written, produced and directed by Tony Leung Hung-Wah.