In 3A.D., during the Eastern Jin Dynasty, parents dress a very pretty, very privileged girl like a boy so she may be educated in a local boarding school. There, she falls in love with a poor, but handsome and industrious young man.

Ko Chow is an undercover cop who is under pressure from all sides. His boss, Inspector Lau, wants him to infiltrate a gang of ruthless jewel thieves; his girlfriend wants him to commit to marriage or she will leave Hong Kong with another lover; and he is being pursued by other cops who are unaware that he is a colleague. Chow would rather quit the force, feeling guilty about betraying gang members who have become his friends.

After his brother was crippled in the ring by a cheating Thai boxer, Chan Hung goes to Thailand to avenge his brother, and finds the key to an omen which may release their family from an ancient curse. He is then caught up in a spiraling web of fate, Buddhist curses, and black magic.

A corrupt magistrate subjects an innocent young bride to inconceivable physical punishments after convicting her of killing her husband.

Pao Lung Sing, a descendant of the legendary Judge Pao Ching Tin, is a 9th degree corrupt judge who changes his tune when he tries to champion a woman Chi Siu-Lin, who was framed for killing her husband. As a result, Pao is forced to flee and through a series of events becomes a 1st degree judge and comes back to wreak havoc and justice on the guilty.

Ko Chun, the God of Gamblers, vows to keep his identity hidden while looking for the gangsters who murdered his pregnant wife.

Ip Man's peaceful life in Foshan changes after Gong Yutian seeks an heir for his family in Southern China. Ip Man then meets Gong Er who challenges him for the sake of regaining her family's honor. After the Second Sino-Japanese War, Ip Man moves to Hong Kong and struggles to provide for his family. In the mean time, Gong Er chooses the path of vengeance after her father was killed by Ma San.

During the Ming Dynasty, Tso Siu Yan, a power-crazed eunuch who rules his desert region of China as if he were the Emperor, ruthlessly thwarts plots against him and sets a trap for one of his enemies at the Dragon Gate Inn.

A rich playboy gets blown up by a gangster when he flirts with the gangster's wife. Through a series of circumstances, his professor makes him a synthetic body that allows him to change into anything he wants.

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.