The final entry in Michael and Johnny Mak's Long Arm of the Law series, Underground Express once again tells a story of gangsters versus police, focusing on the difference between how both factions act depending if they're coming from Hong Kong or Mainland China.

2004 film directed by Wong Kar-Wai

Caught in the middle of a fierce gang war in Macau, a corrupt cop named Sam handles negotiations between two Triad leaders who plan to join forces. He meets a suspicious bald man named Tony, who keeps following him around and disrupting his personal business. But when Sam finds out he's a suspect in a nightclub owner's murder, he's sure his stalker has something to do with it.

Although Tai Jin-sek has a canine partner, Rocky, he does not get along with his neighbour, Man Wing-long, who is a dog-loving veterinarian. When Wing-long's dog goes missing, she is quick to accuse Jin-sek of being the cause. The dynamics between the two neighbours change when Wing-long's friend, Au Ji-san, moves in with Wing-long and Jin-sek quickly falls in love with her. To complicate things further, Wing-long is also fielding a love interest at work, from a fellow veterinarian, Man Hok-yan.

Five young hoodlums sing karaoke, murder, joke around, get beaten up, win and lose women, and learn the value of blind loyalty.

Although Chicken does not make an appearance, Chan Ho Nam finds a new love interest in the form of Mei Ling. Meanwhile, Tung Sing returns to cause trouble again for Hung Hing, in the form of new leader Szeto Ho Nam.

The continuing saga of the life of one of the most powerful men in China in the first half of the 20th Century. By the late 1920's, Luk has established himself as the overlord of Shanghai; a player in politics, business, and the huge underworld. But his generosity begins to strain his finances. Pondering his future, he decides to make a strong commitment to the country, opting for high society over getting high.